The Mekong River in Southeast Asia is one of the most important and productive natural systems in the world. Originating in the Tibetan Plateau, it flows 4,800 km through six nations – China’s Yunnan Province, Myanmar (Burma), Lao PDR, Thailand, Vietnam and Cambodia – before forming a complex delta system with several distributaries and entering the South China Sea. It provides more food than any other river and is second only to the Amazon in its biodiversity. The Mekong is also one of the most threatened in the world.
Approximately 48 major dams, some the largest in the world, are now operating or inevitable, in the Mekong. Another 71 are in prospect. Some of these dams will meet essential domestic power needs, but most will generate revenues through power exports. The epicenter of development is Lao PDR and Cambodia, which is being driven by investments from China and Thailand. On the mainstream of the Xe Kong River, the last free-flowing tributary of the Mekong, feasibility studies for eight large hydropower projects are currently underway by private investors under authorization from the governments of Lao and Cambodia. According to the current designs, NONE of these dams would be able to pass migratory fish, sediments or nutrients. The Mekong River is characterized by a very high percentage of long-range migratory fish. The sediments define the morphology—the physical shape–of the River and its floodplains and delta. This physical substrate determines the quality and variety of the habitats, which, in turn, determine the biological productivity of the system. The associated nutrients nourish the food web, which engenders the amazing biological productivity of the Mekong.
The Mekong dams present insurmountable barriers to the 87% of the Mekong fish species that must move from the ocean, the delta and Tonle Sap up into the large tributaries coming out of Lao, Cambodia and Vietnam to complete their life cycle and reproduce successfully. The Xe Kong portion of the Mekong is the most important for migratory fish production and for contributions of sediments and nutrients that replenish and maintain the habitats that support an extraordinary ecological bounty. They would convert this free-flowing river into a series of sterile impoundments and—quite literally—kill the most productive river in the world. These are flows that nourish the life of the Mekong River and the 70 million people who depend on it intimately for sustenance, transportation, livelihoods, and cultural enrichment.
It is a stark reality that, under current dam development plans and operations, approximately 94% of the sediments and nutrients that now maintain the Lower Mekong will be captured and taken out of the system over the coming decades. This will fundamentally undermine the exceptionally diverse habitats that make the Mekong the most productive river in the world.
The combined effects of sediment deprivation and sea level rise from global climate change have the potential to create a humanitarian crisis of unprecedented proportions. The Mekong delta has been designated by the Intergovernmental Panel on Climate Change as one of three mega deltas (with more than 1 million people) most threatened by coastal erosion due to sea level rise, along with the accompanying storm surges and salinity intrusion. Some 30% of this delta may be permanently lost. But the fate of the remaining 70% depends on maintaining the inflows of sediments and nutrients, and the annual flood pulse that replenishes the delta landscape and the near shore marine environment.
And, the delta is not the only graphic example of the potential impairment. Actually, the productivity of the entire river system, its floodplains, the magically productive Tonle Sap Great Lake (the most productive freshwater lake in the world), the deep holes in the river bottom, the marine fishery, the 32 biological “hotspots”, indeed, every element that accounts for the extraordinary productivity, will be degraded. Most of this can be saved, IF the sediment processes can be maintained in the face of massive upstream development.
The fate of the river, its people, and its most biologically productive features – such as the 3-S basin, the Tonle Sap Great Lake, the Cambodian floodplains, and the delta – will largely be determined within the next 3-5 years. To counteract or prevent the expected physical changes to the Mekong River system and to help shape the course of development, the Natural Heritage Institute (NHI) has been leading an ongoing set of partnerships since late 2010 with the Lower Mekong Basin national governments, the Mekong River Commission, and USAID to formulate and assess more environmentally compatible alternatives for siting, designing and operating hydropower dams in the Mekong River Basin. The objective of the Project is to maintain the natural functions of the Mekong River, especially of the last intact remnant – the Xe Kong tributary – by informing the choices that will be made by the national governments, investors and hydropower customers with regard to the siting, design and operation of hydropower dams throughout the Lower Mekong River system. For these imminent decisions, it is essential to make the case directly to decision-makers, and the the information that will speak most eloquently is technically credible information regarding the alternatives that will preserve most of the hydropower potential while avoiding the adverse impacts on the downstream ecosystems, the people that depend upon them, and on the economic lifespan of the reservoirs.
Project Components & Expected Outcomes
Therefore, NHI has assembled an impressive technical team comprised of NHI Affiliates who provide top expertise in hydrological modeling, hydropower engineering, sediment management, fish biology and fish-passage, and international project management. They work collaboratively with their counterparts at national government agencies and research institutes, and also provide training and knowledge transference. There are three active components set up to achieve the overall project goal: to fundamentally transform the current development plans in the LMB with more benign alternatives.
Upon completion of these components, the project will work with the Government of Vietnam at the highest technical levels to inform them of the hydropower alternatives available to Lao and Cambodia to keep sediment and fish flowing. NHI can only illuminate the best and most sustainable hydropower development alternatives for the national governments and hydropower developers; it cannot itself implement these solutions. Thus, to advance the likelihood that these governments will choose the best course of development, it is important to equip the downstream riparian countries like Vietnam that will feel the impacts of untoward choices—with information in order to raise their voice in an effective manner.
In addition, NHI is working with a world-class production company on a video animation to create a visually compelling and accessible rendition of the technical results of the project as a vehicle to exhibit what sustainable hydropower development means operationally, and how to implement the tools and techniques in a real world context.
Natural Heritage Institute – Project Coordinator
NHI Technical Team:
- Dr. George Annandale (dam engineering and sediment management)
- Dr. Martin Mallen-Cooper (fish by-pass expert)
- Dr. Peter Meier (hydropower economist)
- Dr. Thomas Bernard Wild (hydrologic and sediment modeling)
- Erland Jensen (Cambodia representative: fisheries and M&E expert)
- Min Bunnara (Cambodian national and Project Assistant/Translator)
- Symonekeo Sensathith (Lao PDR Government Relations Associate)
- Mekong River Commission (MRC)
National Counterpart Organizations
- Ministry of Water Resources and Meteorology (MOWRAM)
- Ministry of Mines and Energy (MME)
- Ministry of Environment (MOE)
- Inland Fisheries Research and Development Institute (Fisheries Administration of Ministry of Agriculture) (IFREDI)
- Lao PDR:
- Ministry of Water Resources and Environment (MONRE)
- Ministry of Energy and Mines (MEM)
- Ministry of Planning and Investment (MPI)
- Living Aquatic Resources Research Center (Ministry of Agriculture and Forestry) (LARREC)
- National University of Lao
- Institute for Hydrology, Meteorology and Environment (IMHEN) within the Ministry of Natural Resources and Environment
- Southern Institute for Water Resources & Planning (SIWRP) within the Ministry of Agriculture and Rural Development
 Project funding provided by USAID, the MacArthur Foundation and the Margaret A. Cargill Foundation.