Abstract
The riverine ecosystems of the Mekong River Basin possess the world’s most productive inland fishery and provide highly productive food crops for millions of people annually. The development of hydropower potential in the Mekong River has long been of interest to governments in the region. Among the existing 64 dams, 46 dams have been built in the Lower Mekong Basin (LMB) to produce up to 8650 MW of electricity. Additionally, of the 123 proposed built hydropower dams, eleven hydropower plants have been nominated for the river mainstream and are expected to install a total of 13,000 MW in the LMB countries. However, serious concerns have intensified over the potential negative economic consequences, especially on fisheries and agriculture in Cambodia and Vietnam. To date, most of the concerns have concentrated on the impacts on hydrology, environment, livelihood, and diversity in the LMB attributed to hydropower development. This paper, however, discusses the fishery and agricultural sectors of the LMB and focuses on the downstream floodplains of Cambodia and Vietnam. The dam construction has caused greater losses of biodiversity and fisheries than climate change in the LMB. The reduction of 276,847 and 178,169 t of fish, 3.7% and 2.3% of rice, 21.0% and 10.0% of maize will contribute to a decrease of 3.7% and 0.3% of the GDP of Cambodia and Vietnam, respectively. Lao PDR may benefit the most revenue from electricity generation than the other country in the LMB, as most of the proposed dams are projected in the country. Cambodia burdens 3/4 of the reduction of total capture fishery destruction, whilst Lao PDR, Thailand, and Vietnam endure the remaining 1/3 losses. The tradeoff analyses reveal that losses of capture fisheries, sediment or nutrients, and social mitigation costs are greater than the benefits from electricity generation, improved irrigation, and flood control of the LMB region. The socioeconomic and environmental damage caused by hydropower dams in developing countries, including the Mekong, is greater than the early costs in North America and Europe. It is proposed that dam construction for hydropower in the Mekong River, as well as other rivers in developing countries, should be gradually removed and shifted toward solar, wind, and other renewable resources.
Highlights
The dam construction on the mainstream of the world’s major rivers, experienced in Mississippi, the Yangtze, the Nile, the Yellow, the Congo, as well as the Mekong, has caused losses of wetlands, flood disasters, and poor water quality, agriculture and fishery production, and biodiversity [1]
The 11 dams proposed on the mainstream of the Mekong River by various developers will cover from Pak Beng (Lao PDR) to Sambor (Cambodia), have 240-2,600 MW power capacity, enclose 0.29-620.5 km2 in their reservoir, and relocate 66-19,034 residents in total (Table 1) [21]
The analysis of Ziv et al [16] indicated that the hydropower generation, which is planned to be exported from Lao PDR to Thailand and Vietnam, would have strong and nonlinear tradeoffs with floodplains fishery production
Summary
The dam construction on the mainstream of the world’s major rivers, experienced in Mississippi, the Yangtze, the Nile, the Yellow, the Congo, as well as the Mekong, has caused losses of wetlands, flood disasters, and poor water quality, agriculture and fishery production, and biodiversity [1]. Hydropower production has been developing rapidly, and may increase by more than 70% in the few decades [2] This is affecting aquatic biodiversity and agricultural production in the Amazon, Congo, Mississippi, Yangtze, Nile, and Mekong [3]. There is a recent trend of building new large hydropower dams in developing countries, in megabiodiversity river basins, such as the Amazon, the Congo, and the Mekong, enormous loss in these ecologically important regions is being occurred [1,6,7,8,9]. O(fFidgiustrreic2t,sMinatpheofBdaissitnr)i.ctTshien itmhepBacatssino)f. bTuhieldiimngpadcatsmosfobnutilhdeintrgibduatmarsieosnotfhtehetrLibMutBarhiaevs eofaltshoebLeMenB dhiasvcuesaslesdo rbeeceenntdlyisc[3u]s.sed recently [3]
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