While hydroelectricity is considered as a “green” energy source, suchprojects along the Mekong River have been placing adverse impacts onfishery resources as well as people residing by this water body, expertsargued.
The Mekong River stretches more than 4,800km through sixcountries: China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. Ithas the second biggest fish output in the world, after the Amazon River,said Nguyen Huu Thien, the former head of Vietnam’s National AdvisoryGroup on assessing strategic environmental impacts of hydropower plantson the Mekong River’s mainstream.
About 20 percent of the globalfreshwater fish output, or 2.1 million tonnes, hail from the LowerMekong Basin (LMB), according to a 2010 report on the Mekong RiverCommission Strategic Environmental Assessment of Hydropower on theMekong Mainstream.
Other estimates said the river is home to1,200 fish species. Notably, Vietnam’s Mekong Delta, where the riverflows into the sea, harbours a particular diversity of species, 486,with various sizes from several metres to a few centimetres long.
Fisheryresources play a crucial role in ensuring food security in the LMB,including Cambodia, Thailand, Laos, and Vietnam, which have the highestlevel of per capita freshwater fish consumption.
Around 2 milliontonnes of fish and 0.5 million tonnes of other aquatic species arecaught in the LMB every year in addition to 2 million tonnes of farmedproducts. Therefore, fisheries are pivotal to diversifying people’ssources of living, especially of lower income groups who have to rely onthe river and its resources to earn their daily bread.
Worldresearches indicate that hydropower dams affect ecological andhydrographical systems in rivers since they act as barriers to themovement of fish.
A study on the Amazon River showed that thepresence of dams in this river’s basin hampered some catfish speciesfrom moving over long distances, resulting in a 70 percent decline inthe haul in the lower section.
Meanwhile, most of the speciesthat people catch in the Mekong River are migrants, thus the influenceof hydropower dams on fish’s migration is undeniable. Besides, thesefacilities also interrupt the natural flood cycle familiar to aquaticspecies for thousands of years and make the river bed uninhabitable dueto the loss of habitat and food sources.
Nguyen Huu Thienexplained that the LMB and the Mekong Delta in particular has a floodand a dry season along with two alternated transitional periods. Theseperiods are important to the entire eco-system as they act as a signalinforming aquatic species that it is time to migrate, breed, or do otheractivities in their life cycle.
Hydropower dams’ storage andrelease of water will shorten or make transitional periods to disappearor turn the dry season into the flood one and vice versa. As a result,aquatic species will become confused about seasons and unable to followtheir normal activities, he added.
The 2010 report also saidhydropower dams will block the flow of alluvium, thus reducing thesource of food for fish in coastal waters.
It is estimatedthat about 100 million tonnes of alluvium carrying along 16,000 tonnesof nutrition substances are left in coastal waters of this delta everyyear, helping the Mekong Delta has an annual marine product output ofbetween 500,000-726,000 tonnes.
Hydroelectricity has long beenconsidered as a “green” energy source since they do not emit greenhousegases during operation, theoretically help control water currents, andprevent floods and droughts in downstream areas.
However, thedevelopment of these facilities along major river systems like theMekong River needs to be thoroughly contemplated by all countries thatit traverses.
Nguyen Nhan Quang, an expert on river basinmanagement, said it is essential to clarify possible impacts of dams onmigrant species, water currents, and the alluvium flow in order to avoidconsequences of future hydropower projects and help countries in theLMB realise the Agreement on the cooperation for the sustainabledevelopment of the Mekong River Basin.
The Mekong RiverCommission reported that by 2013, there were at least 77 hydropowerprojects planned on Mekong River's tributaries and 11 mainstreamhydropower projects/dams planned in the LMB, which is home to more than60 million people.-VNA
The Mekong River stretches more than 4,800km through sixcountries: China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. Ithas the second biggest fish output in the world, after the Amazon River,said Nguyen Huu Thien, the former head of Vietnam’s National AdvisoryGroup on assessing strategic environmental impacts of hydropower plantson the Mekong River’s mainstream.
About 20 percent of the globalfreshwater fish output, or 2.1 million tonnes, hail from the LowerMekong Basin (LMB), according to a 2010 report on the Mekong RiverCommission Strategic Environmental Assessment of Hydropower on theMekong Mainstream.
Other estimates said the river is home to1,200 fish species. Notably, Vietnam’s Mekong Delta, where the riverflows into the sea, harbours a particular diversity of species, 486,with various sizes from several metres to a few centimetres long.
Fisheryresources play a crucial role in ensuring food security in the LMB,including Cambodia, Thailand, Laos, and Vietnam, which have the highestlevel of per capita freshwater fish consumption.
Around 2 milliontonnes of fish and 0.5 million tonnes of other aquatic species arecaught in the LMB every year in addition to 2 million tonnes of farmedproducts. Therefore, fisheries are pivotal to diversifying people’ssources of living, especially of lower income groups who have to rely onthe river and its resources to earn their daily bread.
Worldresearches indicate that hydropower dams affect ecological andhydrographical systems in rivers since they act as barriers to themovement of fish.
A study on the Amazon River showed that thepresence of dams in this river’s basin hampered some catfish speciesfrom moving over long distances, resulting in a 70 percent decline inthe haul in the lower section.
Meanwhile, most of the speciesthat people catch in the Mekong River are migrants, thus the influenceof hydropower dams on fish’s migration is undeniable. Besides, thesefacilities also interrupt the natural flood cycle familiar to aquaticspecies for thousands of years and make the river bed uninhabitable dueto the loss of habitat and food sources.
Nguyen Huu Thienexplained that the LMB and the Mekong Delta in particular has a floodand a dry season along with two alternated transitional periods. Theseperiods are important to the entire eco-system as they act as a signalinforming aquatic species that it is time to migrate, breed, or do otheractivities in their life cycle.
Hydropower dams’ storage andrelease of water will shorten or make transitional periods to disappearor turn the dry season into the flood one and vice versa. As a result,aquatic species will become confused about seasons and unable to followtheir normal activities, he added.
The 2010 report also saidhydropower dams will block the flow of alluvium, thus reducing thesource of food for fish in coastal waters.
It is estimatedthat about 100 million tonnes of alluvium carrying along 16,000 tonnesof nutrition substances are left in coastal waters of this delta everyyear, helping the Mekong Delta has an annual marine product output ofbetween 500,000-726,000 tonnes.
Hydroelectricity has long beenconsidered as a “green” energy source since they do not emit greenhousegases during operation, theoretically help control water currents, andprevent floods and droughts in downstream areas.
However, thedevelopment of these facilities along major river systems like theMekong River needs to be thoroughly contemplated by all countries thatit traverses.
Nguyen Nhan Quang, an expert on river basinmanagement, said it is essential to clarify possible impacts of dams onmigrant species, water currents, and the alluvium flow in order to avoidconsequences of future hydropower projects and help countries in theLMB realise the Agreement on the cooperation for the sustainabledevelopment of the Mekong River Basin.
The Mekong RiverCommission reported that by 2013, there were at least 77 hydropowerprojects planned on Mekong River's tributaries and 11 mainstreamhydropower projects/dams planned in the LMB, which is home to more than60 million people.-VNA
