- October 10, 2021 4:57 PM
- March 10, 2020 3:53 AM
- April 1, 2023 11:35 AM
Thmey Thmey’s Sao Phal Niseiy caught up with the Stimson Center’s Brian Elyer who explains the current situation of the Mekong River in his capacity as Energy, Water & Sustainability Program Director for Southeast Asia.
Sao Phal Niseiy: A recent report conducted by Eyes on Earth reveals that China has limited water flow in the Mekong River, triggering an outpouring of concern among people in downstream countries. What’s your take on this issue?
Brian Eyler: The Eyes on Earth report lifts the veil on China's upstream dam operations for the first time and packs an important message that shows when and to what extent China's dams alter the natural flow of the Mekong River. Dams inevitably will alter flow, particularly in river systems with extreme swings from a flood season to a dry season.
But the Eyes on Earth report used modeling techniques derived from satellite data to show particularly how in 2019 China's dams broke the Mekong flood pulse in 2019 and exacerbated downstream drought conditions along the Mekong mainstream. The annual flood pulse is critically important to drive the natural resource base of the Mekong which produces 20 percent of the world's freshwater fish catch and drives the livelihoods of tens of millions of people downstream.
The 2019 drought that played out in the lower Mekong basin and some of southern Yunnan's part of the basin broadly was a climate driven phenomenon mainly caused by extremely low levels of precipitation. However, the upstream of the basin, particularly the area above Dali, received higher than normal amounts of precipitation throughout the traditional monsoon season.
Eyes on Earth's model shows that the amount of wetness in the upper basin was enough to cause a natural monsoon pulse at the Chiang Saen gorge in Thailand and that would have translated down through the Mekong system. However, China's dams restricted nearly all of that water from the Mekong mainstream, so the places along the mainstream and areas like northeast Thailand, the Tonle Sap, and the Mekong Delta which all take water from the mainstream received compounding effects of China's dams and drought during this time. If China's 11 dams were not there, much more water would have been available along the Mekong mainstream and in the areas that take water from the mainstream.
Sao Phal Niseiy: What are the most notable implications for downstream countries in general and Cambodia in particular?
Brian Eyler: This finding suggests the cities and communities along the Mekong mainstream and those areas that take on water from the mainstream (i.e. northeast Thailand provinces, the Tonle Sap, Mekong Delta) would have had more water available during the historic 2019-20 drought. The findings suggest the river level would not have hit rock bottom and the annual reversal of the Tonle Sap could have occurred earlier than the end of August 2019 which would have produced a higher yield in fish catch not only in the Tonle Sap but throughout the entire basin.
From a long-term view, we’ve known for a long time that China’s upstream dams are releasing more water in the dry season and raising the level of the river as well as holding back water during the monsoon season. The Eyes on Earth study provides a sense of how long and to what extent China’s upstream dams alter flow. The Mekong needs to transition each year from extreme highs to extreme lows in order to produce its natural resource base for the tens of millions who rely on it – leveling out the river level over time erodes that resource base by breaking down critical ecological processes.
Sao Phal Niseiy: To you, how important this study is in helping the Mekong countries to deal with any current challenges, especially to deal with what China has been doing?
Brian Eyler: This study provides a method for understanding how much water should be available to downstream countries if China’s dams weren’t altering flow. Downstream countries would be wise to adopt these methods to improve transparency over the operations of China’s dams and push for a more equitable share of water to the downstream.
Sao Phal Niseiy: You are the author of the book entitled “Last Days of the Mighty Mekong,” and the book has delivers a much clearer picture of how unsustainable development of the Mekong region has been, which all potentially ends up with social as well ecological repercussions. Can you briefly tell us the most pressing challenges facing the river?
Brian Eyler: This is a very complex subject, but the issue goes far beyond dams. Dams block flows of water, fish migration, and sediment passage – all useful in keeping the river healthy and economies strong in the Mekong. But illegal and excess extraction of sand, sediment, and fish from the system also challenges the ecological viability of the Mekong system and the ability of humans to continue living in the basin, particularly in the Mekong Delta and along the Tonle Sap. A range of climate change issues exacerbate all of these problems, serving up an extremely difficult to navigate future for the fragile Mekong system.
Sao Phal Niseiy: The Mekong River is a sort of artery for the region, but more power you have over the Mekong, the more leverage you have when dealing with other issues, whether they’re political, social or security based – what are your thoughts on this?
Brian Eyler: I think downstream countries have plenty of options to solve some of the problems around them through more sustainable planning processes, but ultimately regional cooperation can pave the way for a stronger and more autonomous Mekong region. Transparent, evidence-based processes like Eyes on Earth’s approach can help push cooperation forward.
Sao Phal Niseiy: We all agree that the most precious thing on earth will be water. As the impacts of climate change have been intensifying, it is likely that Mekong countries will experience more frequent droughts as well as extreme weather. Do you think a future competition for water could spill over into an open conflict?
Brian Eyler: I do not think this will result in conflict over water. Water war theories are overexaggerated. However, environmental crises derived from poor planning processes and man-made climate change effects can destabilize the region and set it on the path toward various kinds of conflicts.