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Much of the world’s greatest rivers root from the mighty Himalayas. One of these rivers, the Mekong, flows from Tibet, China, to the south of Vietnam (Mekong Basin, n.d). The river is the backbone of Southeast Asia, passing through Chinese Tibet and Yunnan, as well as Myanmar, Thailand, Laos, Cambodia, and Vietnam (Mekong Basin, n.d). However, with China being the most populous country in the world as of 2022, their government needs to supply their vast population with electricity (Eyler, 2020). In turn, China has built over 30 large-scale dams in Yunnan and Tibet (Eyler, 2020). However, the consequences are severe to the countries of Southeast Asia, its biodiversity, and its economy. Consequences which may have been done deliberately or out of desperation.
Why does the Mekong matter?
In terms of fish biodiversity in rivers worldwide, the Mekong ranks second place which is just behind the mighty Amazon River (Mekong River, n.d). Furthermore, the Mekong River is in fact the world’s largest inland fishery, with an estimated haul of 2.6 million tons of fish per year (Mekong River, n.d).
In addition to its great fish biodiversity, the Mekong River and its floodplains are home to approximately 20,000 species of plants, 1,200 bird species, 430 mammalian species, as well as 800 reptilian and amphibian species. Furthermore, according to the WWF, more than 1300 new species have been logged in this region since 1997 (Mekong River, n.d). The Mekong is also home to some of the world's most rare and endangered species, such as the Saola and the Irrawaddy Dolphin (Mekong River, n.d).
Looking into Geopolitics
Geopolitics have recently revealed strange and often mischievous decisions made by some of the world’s superpowers. From a western standpoint, China is an example of this with its territorial claims to restore the lands of the former Qing Empire, claims in the South China Sea, and also to mention its dam building along the Himalayas and the tributaries of the Mekong (Krishnankutty, 2020). Since the majority of major rivers in East Asia spring from Tibet, China has control of the tributaries that converge to form the Mekong. With 13 operating dams in China, and 6 in construction, China has control over the water-levels of the Mekong (Eyler, 2020). This means that China is able to assert control over the river to serve its own needs while forcing Southeast Asia to its influence (Eyler, 2020). With the combination of the annual El Niño, the impacts become more severe with more intense droughts and lower river basins (Eyler, 2020). According to a wet season precipitation map of Southeast Asia during 2000- 2018, the average wet season tends to be more wet in China; in contrast, the wet season is more dry in Southeast Asia when compared to China (Eyler, 2020).
The Water Rising Trends of the Mekong
Chinese dams are shown to affect the water flows of Mekong. During the wet seasons, the water flows are seen to be reduced whereas during the dry seasons the water flows are shown to be increased. Storage dams primarily contributed to the increased water flow during the dry seasons. This is due to the discharge of water for energy production. 12.65 billion cubic metres of water discharged from the Jinghong hydropower reservoir during March to May 2016. This totalled to 40-89% of flows to various sections of the Mekong river. If these releases did not occur flows would have been 47% lower at Jinghong, 44% lower at Chiang Saen, 38% lower at Nong Khai and 22% lower at Stung Treng (MRC, n.d.).
Annual Disasters to come with Dam-Building
From feeding jungles, irrigating crops for millions of people, and supporting the tonle sap lake-the most productive fishery on the planet, the Mekong river has significant importance. However, the annual disaster to come with the hydropower dams will have a devastating effect on the Mekong river and its services. These include unseasonable flooding and droughts, high water levels in wet seasons and drops in the amounts of sediment carried by the river, with drastic consequences for biodiversity and fisheries (Ronny, 2022).
How is the local biodiversity downstream affected?
During the last century, the water-levels of the Mekong River faced drastic changes in rises and reductions. Much of the countries in Southeast Asia depend on the Mekong River to generate hydroelectric energy. However, some of these countries don’t have enough money to sustain the ecology and generate hydroelectricity. An example of this scenario can be seen in the nation of Cambodia, where frequent blackouts are common across the country (Sukanan, 2019). Cambodia often purchases it’s hydroelectricity from neighboring countries like Thailand (Sukanan, 2019); however, there is only so much a country can do with constantly purchasing electricity. Therefore, this is why the Cambodian government is looking towards building more hydroelectric dams along the Mekong (Sukanan, 2019). While beneficial for the economy, the dams may affect the migration of fish species from Tonel Sap to the Mekong in Northern Cambodia during the monsoon season. Furthermore, much of South Cambodia’s economy is dependent on fishing (Sukanan, 2019). Therefore, these migrations play a big role in both the biodiversity and economy of Cambodia.