Major dam construction projects have become a favorite pastime of some autocratic governments, with China leading the way.
However, far from protecting against water shortages, as supporters promise, large dams are contributing to river depletion and severely exacerbating parched conditions.
Nowhere is this more apparent than in the basin of the Mekong River, which is running at a historically low level.
Known as the “mother of waters” in Laos and Thailand, the Mekong flows from the Chinese-controlled Tibetan Plateau to the South China Sea, through Myanmar, Laos, Thailand, Cambodia and Vietnam.
Farmers in the river basin, Asia’s rice bowl, produce enough rice to feed 300 million people per year.
The basin also boasts the world’s largest inland fishery, accounting for an estimated 25 percent of the global freshwater catch.
This vital waterway is now under threat, largely owing to a series of Chinese-built mega-dams near the border of the Tibetan Plateau, just before the river crosses into Southeast Asia.
The 11 dams currently in operation together have an electricity-generating capacity of 21,300 megawatts — more than the installed hydropower capacity of all the downriver countries combined. They are wreaking environmental, economic and geopolitical havoc.
For starters, by reducing the flow of freshwater and nutrient-rich sediment from the Himalayas into the sea, these mega-dams are causing a retreat of the Mekong Delta in southern Vietnam.
The resulting seawater intrusion is forcing rice farmers to switch to shrimp farming or growing reeds.
Moreover, according to a Mekong River Commission study, hydropower development through 2040 — which includes several more Chinese mega-dams under construction or planned — will result in a 40 to 80 percent decline in fish stocks (by biomass).
Migratory fish will disappear across much of the basin, which presently is second only to the Amazon in terms of fish species diversity.
Dams are also disrupting the Mekong’s annual flooding cycle, which helps to refertilize farmland naturally by spreading nutrient-rich silt, besides opening giant fish nurseries.
Earlier this summer, China’s maintenance work on its Jinghong Dam resulted in the release of torrents of water. The resulting floods in Thailand and Laos destroyed crops and disrupted fish, damaging local people’s livelihoods.
China then refilled the dam using water from the Mekong. The drop in downstream water levels compounded water-scarce conditions, the result of a 40 percent shortfall in monsoon rains in June and last month.
Instead of overflowing during the summer, the river reached record-low levels, depleting fish stocks and setting back rice production, the commission report said.
In Thailand, overall reservoir water availability has sunk by 24 percent year-on-year, in a drought so severe that the government, led by Thai Prime Minister Prayuth Chan-ocha, has ordered the armed forces to help respond.
Regardless, China has shown no sign that its dam-building frenzy is abating. For the Chinese government, mega-dams are proud symbols of engineering prowess.
So it not only has more large dams in operation than the rest of the world combined; it also has the single largest — the Three Gorges Dam — and plans to build an even bigger one near the disputed Himalayan border with India.