By the Numbers: Drought on the Mekong River

The data driving Asia

Southeast Asia is experiencing its worst drought in decades, with Vietnam, Cambodia, Laos and Thailand suffering the brunt of it. The drought began in late 2015 and is expected to continue through June 2016. Effects of the drought have been exacerbated by a severe El Niño episode, but environmental experts believe increased building of hydroelectric dams on the Mekong River has placed additional pressure on the river and the people who depend on it for survival. The Southeast Asia program at CSIS takes a quantitative look at dams on the Mekong, losses from the drought, and countries’ responses to the crisis:


Hydroelectric dams China has built on the upper Mekong River. The river carries an estimated 45 percent of the Mekong basin’s water during the dry season, and experts fear that dams obstruct its natural ebb and flow. China plans to construct another 14 dams on its portion of the Mekong in coming years.


Number of dams planned for the Lower Mekong River and its tributaries. In addition, 11 dams are planned for the Mekong mainstream in Cambodia, Laos, and Thailand.

$1.2 billion

Projected losses in dollars to fishing and agriculture in Vietnam and Cambodia if the 11 proposed dams on the mainstream Mekong are built. The dams eliminate sediments that are necessary for restoring eroded soil, and would block fish migration pathways.

Parched rice field in Can Tho, Vietnam. Source: Wikimedia user dragfyre, used under a creative commons license.

Parched rice field in Can Tho, Vietnam. Source: Wikimedia user dragfyre, used under a creative commons license.

2.3 billion

The amount of water, in cubic meters, that China released from its Jinghong Hydropower Station on March 15 to alleviate drought effects on the lower Mekong. Only 3-4 percent of this water will reach Vietnam’s Mekong delta, with the rest being absorbed by parched regions along the way.


Acres of rice in Vietnam damaged or destroyed by drought and salinization since the end of 2015. Low levels of freshwater combined with rising sea levels have pushed saltwater from the South China Sea into the shallow Mekong River, destroying rice crops.

2 million

Projected shortfall, in tons, for Thailand’s rice output 2016-2017. The Thai government plans to spend millions of dollars to stabilize rice prices and train farmers how to grow less water-intensive crops.


People who do not have enough water for daily usage in Vietnam. More than half of the provinces in Vietnam — 39 out of 63 — have requested help from the central government to combat the effects of El Niño and the drought.



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