Keep the mainstream Xe Kong free flowing through Lao PDR:
Today, the mainstream of the Xe Kong tributary is the last undeveloped major tributary in the Mekong River Basin, and its natural function remain unimpaired down the mainstream Mekong, through the Cambodian floodplains and the Tonle Sap Great Lake through the Vietnam Delta, to the South China Sea. However, there are currently seven hydropower dam sites on the Xe Kong that are being actively studied and the lowest six are located right in the prime migratory fish spawning habitat of the mainstream river. The lower reach of the Xe Kong River is characterized by a high level of fish biodiversity, amounting to 175 species, including 64 migratory fish species. Fifteen species are exclusive to the Xe Kong River; they are neither found in any other Mekong River tributary nor anywhere else in the world. Many of these species must migrate upstream to spawning areas. Completing these migrations require unobstructed passage upstream, as well as the capacity for adults, larvae and juveniles to migrate or drift downstream. The livelihood benefit of the fishery resource, in terms of nutrition, income and employment, is crucial, particularly for rural poor, who have few other livelihood options.
The degree of impact that the potential Xe Kong dams and reservoirs would cause to migratory fish, due to both the barrier they pose to fish migration and to the inundation of riverine spawning habitats, depends on their size and, most important, their location. The further downstream the dam, the more impactful it would be. The lower six would create an absolute barrier to fish migration as it is not feasible to engineer fish by-passes around these large dams, and each would create impoundments that would inundate these habitats. The combined effect would be to turn what is now a river ecosystem into a series of lakes which would not sustain the hundreds of migratory species that require these habitats to survive.
NHI has been asked by the Ministry of Energy and Mines and and other relevant agencies of the Government of Lao to advise it in implementing the new Policy on Sustainable Hydropower Development, decreed by the Prime Minister on January 12, 2015, by creating a “Master Plan” for hydropower development in the Xe Kong basin that will show how future dams can be sited above existing barriers to migration, designed to discharge sediments and nutrients, and operated to maintain a natural variability of flow with without sacrificing Lao’s development goals.
In the Mekong River Basin, the principal sustainability consideration in hydropower development is the avoidance of impairment of the exceptional productivity of the Mekong fishery. Therefore, the “master plan” will take account of, but greatly improve on, the several previous hydropower development plans that have been promulgated by JICA, among others, by presenting the opportunities for:
- siting future hydropower dams in locations that do not inundate or block fish passage into the habitats that are most valuable for migratory fish breeding and rearing;
- designing the dams to efficiently pass sediments and nutrients; and
- operating the dams to maintain a semblance of the natural flow patterns, including the seasonal variability of flows, to enable the fish to access and use the high-value riverine and floodplain habitats.
- Expected outputs: Master Plan of Sustainable Hydropower Development for the Xe Kong basin, Implementation Plan, Cumulative & Transboundary Environmental Impact Assessment.
- Expected outcome: Adoption of the Master Plan as the official development plan of the GoL, prescribing the project for which it will entertain competitive proposals from developers.
- 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