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1. High Resolution Modeling of River‐Floodplain‐Reservoir Inundation Dynamics in the Mekong River Basin

   https://doi.org/10.1029/2019WR026449  

   Shin, Sanghoon; Pokhrel, Yadu; Yamazaki, Dai; Huang, Xiaodong; Torbick, Nathan; Qi, Jiaguo; Pattanakiat, Sura; Ngo‐Duc, Thanh; Nguyen, Tuan Duc (April 2020, Water Resources Research)

   Abstract Numerous studies have examined the changes in streamflow in the Mekong River Basin (MRB) using observations and hydrological modeling; however, there is a lack of integrated modeling studies that explicitly simulate the natural and human‐induced changes in flood dynamics over the entire basin. Here we simulate the river‐floodplain‐reservoir inundation dynamics over the MRB for 1979–2016 period using a newly integrated, high‐resolution (~5 km) river hydrodynamics‐reservoir operation model. The framework is based on the river‐floodplain hydrodynamic model CaMa‐Flood in which a new reservoir operation scheme is incorporated by including 86 existing MRB dams. The simulated flood extent is downscaled to a higher resolution (~90 m) to investigate fine‐scale inundation dynamics, and results are validated with ground‐ and satellite‐based observations. It is found that the historical variations in surface water storage have been governed primarily by climate variability; the impacts of dams on river‐floodplain hydrodynamics were marginal until 2009. However, results indicate that the dam impacts increased noticeably in 2010 when the basin‐wide storage capacity doubled due to the construction of new mega dams. Further, results suggest that the future flood dynamics in the MRB would be considerably different than in the past even without climate change and additional dams. However, it is also found that the impacts of dams can largely vary depending on reservoir operation strategies. This study is expected to provide the basis for high‐resolution river‐floodplain‐reservoir modeling for a holistic assessment of the impacts of dams and climate change on the floodpulse‐dependent hydro‐ecological systems in the MRB and other global regions. 

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2. Re-operating dams in the Mekong

   https://doi.org/10.1038/s41893-022-00998-2  

   Pokhrel, Yadu; Tiwari, Amar Deep (December 2022, Nature Sustainability)
3. Maintaining perspective of ongoing environmental change in the Mekong floodplains

   https://doi.org/10.1016/j.cosust.2019.01.002  

   Arias, Mauricio E; Holtgrieve, Gordon W; Ngor, Peng Bun; Dang, Thanh Duc; Piman, Thanapon (April 2019, Current Opinion in Environmental Sustainability)
4. Dynamical Impact of the Mekong River Plume in the South China Sea

   https://doi.org/10.1029/2021JC017572  

   Zeng, Xiyuan; Bracco, Annalisa; Tagklis, Filippos (April 2022, Journal of Geophysical Research: Oceans)

   Abstract Near the ocean surface, river plumes influence stratification, buoyancy and transport of tracers, nutrients and pollutants. The extent to which river plumes influence the overall circulation, however, is generally poorly constrained. This work focuses on the South China Sea (SCS) and quantifies the dynamical impacts of the Mekong River plume, which is bound to significantly change in strength and seasonality in the next 20 years if the construction of over hundred dams moves ahead as planned. The dynamic impact of the freshwater fluxes on the SCS circulation are quantified by comparing submesoscale permitting and mesoscale resolving simulations with and without riverine input between 2011 and 2016. In the summer and early fall, when the Mekong discharge is at its peak, the greater stratification causes a residual mesoscale circulation through enhanced baroclinic instability. The residual circulation is shaped as an eddy train of positive and negative vorticity. Submesoscale fronts are responsible for transporting the freshwater offshore, shifting eastward the development of the residual mesoscale circulation, and further strengthening the residual eddy train in the submesoscale permitting case. Overall, the northward transport near the surface is intensified in the presence of riverine input. The significance of the mesoscale‐induced and submesoscale‐induced transport associated with the river plume is especially important in the second half of the summer monsoon season, when primary productivity has a secondary maximum. Circulation changes, and therefore productivity changes, should be anticipated if human activities modify the intensity and seasonality of the Mekong River plume. 

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5. Climatic and Anthropogenic Controls on Groundwater Dynamics in the Mekong River Basin

   https://doi.org/10.5281/zenodo.7968319  

   Kabir, Tamanna; Pokhrel, Yadu; Felfelani, Farshid (January 2023, Zenodo)

   Datasets for the paper (Climatic and Anthropogenic Controls on Groundwater Dynamics in the Mekong River Basin)- Observed streamflow data from Mekong River Commission (MRC) Groundwater observations from Tiwari et al., (2023; Sci. Data) Groundwater simulation outputs from CLM5 for Mekong River Basin. 

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