Hydropower dams of the Mekong River basin: A review of their hydrological impacts

Conflict and cooperation are key governance challenges in transboundary river basin governance, especially in the Mekong River Basin. Hydropower dams have been at the center of such a conflict and cooperation that are useful metrics to assess the level and intensity of conflict and cooperation in transboundary river basin governance. This study examines transboundary river basin cooperation in the Mekong through the lens of hydropower dam projects. It uses a literature review and a case study of the Lower Sasan 2 (LS2) Dam to analyze the conflict and cooperation in the Mekong region, from the era of the US influence in the Cold War, the post-Cold War period, and the present-day with the rise of China. It concludes that Mekong river basin cooperation has evolved as a result of external influences and internal competition by riparian states over Mekong resources. The LS2 was identified in 1961 by US-supported hydropower studies and then by the GMS/ADB in 1998, but left unattended until 2007 when Vietnam signed an agreement with Cambodia to undertake a feasibility study in 2008. It took 16 years to get the LS2 built by a Chinese company in 2014 and completed it in 2017. Through the process, the states, powerful external actors, financial institutions, and private sector actors have politicized the LS2 studies, design, and construction. Cambodia, as a weak downstream state, has had to and must continue to position itself strategically in its relationships with these hydro-hegemons to compete for hydropower dam projects and protect its interests. The rise of China has induced the changing relationship between riparian states. Many hydropower dams were built with Chinese funding. Cambodia has also enjoyed its close ties with China, and the building of the LS2 dam by a Chinese company contributes to changing its positions in the Mekong cooperation but suffers environmental and social impacts.

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A New Remote Sensing Approach to Enrich Hydropower Dams’ Information and Assess Their Impact Distances: A Case Study in the Mekong River Basin

Remote Sensing ◽

10.3390/rs11243016 ◽

2019 ◽

Vol 11 (24) ◽

pp. 3016

Author(s):

Zihan Lin ◽

Jiaguo Qi

Keyword(s):

Remote Sensing ◽

Land Use ◽

Land Cover ◽

River Basin ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Mekong River ◽

Mekong River Basin ◽

Hydropower Dam ◽

Hydropower Dams

Hydropower dam information such as construction and completion timings is often incomplete and missing in existing dam databases, and the hydropower dam’s adjacency impact distance, which is important to the surrounding environment, is also lacking for many dams. In this study, we developed a new remote sensing approach to specifically determine the timings and to assess the influencing distance on land use and land cover at the above and below dam areas. We established the new remote sensing method by identifying levels shifts in trajectories of Normalized Difference Vegetation Index (NDVI) indicators and by identifying the change point in entropy coefficient of variation (CV) variations to allow an auto-acquisition of the information above at the water basin level. We used three geospatial datasets including 1) a 30-year Landsat time series, 2) an annual Landsat Normalized Difference Vegetation Index (NDVI) composite, and 3) digital elevation model (DEM) data. We applied the proposed method to the Mekong River Basin (MRB) in Southeast Asia, where hydropower dam constructions have increased significantly since the 1990s. Results suggested that we were able to obtain the desired information for 67 Mekong hydropower dams successfully. Pearson correlation tests were used to validate timing results against official records, and the correlation coefficients were found to be 0.96 and 0.90, respectively, for construction and completion timing determination. We discovered that the buffer radius of a Mekong dam’s adjacency impact on land use and land cover was usually 4.0-km and 2.5-km in the above and below dam area. The data determined from this study may fill important information gaps in existing dam databases, and the approach developed in this case may be generalized to the other watersheds of the world, where hydropower dams exist. However, essential dam information is either incomplete or unavailable.

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Unveiling a Rich Tapestry of the Mekong River Basin through Ten Analyses Based on Three Keywords

Asia Review ◽

10.24987/snuacar.2020.02.9.2.405 ◽

2020 ◽

Vol 9 (2) ◽

pp. 405-412

Author(s):

KoUn Kim

Keyword(s):

River Basin ◽

Mekong River ◽

Mekong River Basin

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Intercomparison of ten ISI-MIP models in simulating discharges along the Lancang-Mekong River basin

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.144494 ◽

2021 ◽

Vol 765 ◽

pp. 144494

Author(s):

He Chen ◽

Junguo Liu ◽

Ganquan Mao ◽

Zifeng Wang ◽

Zhenzhong Zeng ◽

...

Keyword(s):

River Basin ◽

Mekong River ◽

Mekong River Basin ◽

Mip Models

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The Impacts of Hydropower Dams in the Mekong River Basin: A Review

Water ◽

10.3390/w13030265 ◽

2021 ◽

Vol 13 (3) ◽

pp. 265

Author(s):

Akarath Soukhaphon ◽

Ian G. Baird ◽

Zeb S. Hogan

Keyword(s):

River Basin ◽

River System ◽

Economic Security ◽

Mekong River ◽

Aquatic Biodiversity ◽

Environmental Impact Assessments ◽

The Social ◽

Hydropower Dams ◽

River Hydrology ◽

Riparian Communities

The Mekong River, well known for its aquatic biodiversity, is important to the social, physical, and economic health of millions living in China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. This paper explores the social and environmental impacts of several Mekong basin hydropower dams and groupings of dams and the geographies of their impacts. Specifically, we examined the 3S (Sesan, Sekong Srepok) river system in northeastern Cambodia, the Central Highlands of Vietnam, and southern Laos; the Khone Falls area in southern Laos; the lower Mun River Basin in northeastern Thailand; and the upper Mekong River in Yunnan Province, China, northeastern Myanmar, northern Laos, and northern Thailand. Evidence shows that these dams and groupings of dams are affecting fish migrations, river hydrology, and sediment transfers. Such changes are negatively impacting riparian communities up to 1000 km away. Because many communities depend on the river and its resources for their food and livelihood, changes to the river have impacted, and will continue to negatively impact, food and economic security. While social and environmental impact assessments have been carried out for these projects, greater consideration of the scale and cumulative impacts of dams is necessary.

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Spatiotemporal assessment of land use/land cover change and associated carbon emissions and uptake in the Mekong River Basin

Remote Sensing of Environment ◽

10.1016/j.rse.2021.112336 ◽

2021 ◽

Vol 256 ◽

pp. 112336

Author(s):

Xiaojing Tang ◽

Curtis E. Woodcock ◽

Pontus Olofsson ◽

Lucy R. Hutyra

Keyword(s):

Land Use ◽

Land Cover ◽

Land Cover Change ◽

River Basin ◽

Carbon Emissions ◽

Mekong River ◽

Land Use Land Cover ◽

Mekong River Basin

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Meteorological and hydrological droughts in Mekong River Basin and surrounding areas under climate change

Journal of Hydrology Regional Studies ◽

10.1016/j.ejrh.2021.100873 ◽

2021 ◽

Vol 36 ◽

pp. 100873

Author(s):

Yishan Li ◽

Hui Lu ◽

Kun Yang ◽

Wei Wang ◽

Qiuhong Tang ◽

...

Keyword(s):

Climate Change ◽

River Basin ◽

Mekong River ◽

Mekong River Basin ◽

Surrounding Areas ◽

Hydrological Droughts

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Attribution of Long-Term Evapotranspiration Trends in the Mekong River Basin with a Remote Sensing-Based Process Model

Remote Sensing ◽

10.3390/rs13020303 ◽

2021 ◽

Vol 13 (2) ◽

pp. 303

Author(s):

Shi Hu ◽

Xingguo Mo

Keyword(s):

Remote Sensing ◽

Water Resources ◽

Solar Radiation ◽

River Basin ◽

Mekong Delta ◽

Mekong River ◽

Catchment Management ◽

Mekong River Basin ◽

Area Index ◽

Available Water

Using the Global Land Surface Satellite (GLASS) leaf area index (LAI), the actual evapotranspiration (ETa) and available water resources in the Mekong River Basin were estimated with the Remote Sensing-Based Vegetation Interface Processes Model (VIP-RS). The relative contributions of climate variables and vegetation greening to ETa were estimated with numerical experiments. The results show that the average ETa in the entire basin increased at a rate of 1.16 mm year−2 from 1980 to 2012 (36.7% of the area met the 95% significance level). Vegetation greening contributed 54.1% of the annual ETa trend, slightly higher than that of climate change. The contributions of air temperature, precipitation and the LAI were positive, whereas contributions of solar radiation and vapor pressure were negative. The effects of water supply and energy availability were equivalent on the variation of ETa throughout most of the basin, except the upper reach and downstream Mekong Delta. In the upper reach, climate warming played a critical role in the ETa variability, while the warming effect was offset by reduced solar radiation in the Mekong Delta (an energy-limited region). For the entire basin, the available water resources showed an increasing trend due to intensified precipitation; however, in downstream areas, additional pressure on available water resources is exerted due to cropland expansion with enhanced agricultural water consumption. The results provide scientific basis for practices of integrated catchment management and water resources allocation.

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