Letters from the Mekong

Issue Brief

This issue brief, the first in a new series of “Letters from the Mekong,” discusses the current status of hydropower planning, development, cooperation and decision-making in the Mekong Basin. Hydropower dams, especially large dams on major tributaries and mainstreams, have long been highly controversial because of their negative impact on other components of the water-food-energy-livelihoods “nexus.” In the lower, Southeast Asian half of the 5,080-kilometer Mekong River, with an ecology that has evolved over millions of years to annual extremes of flood and drought, the primary problem of large dams is that they interfere with the river’s life-giving hydrology, block the spawning migration of highly important catch fisheries. Dams also trap nutrient rich sediment needed to replenish farm fields and sustain the Mekong Delta, already one of the world’s most threatened coastal zones due to climate change and sea level rise.