Articles | Volume 22, issue 3
https://doi.org/10.5194/nhess-22-967-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/nhess-22-967-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
The Cambodian Mekong floodplain under future development plans and climate change
Alexander J. Horton
CORRESPONDING AUTHOR
Water and Development Research Group, Aalto University, Tietotie 1E, 02150 Espoo, Finland
Nguyen V. K. Triet
GFZ German Research Centre for Geosciences, Section Hydrology, Potsdam, 14473, Germany
Long P. Hoang
Water Systems and Global Change Group, Wageningen University, P.O. Box 47, 6700 AA Wageningen, the Netherlands
VNU School of Interdisciplinary Studies, Vietnam National University, 144 Xuan Thuy, Hanoi, Vietnam
Sokchhay Heng
Faculty of Hydrology and Water Resources Engineering, Institute of Technology of Cambodia, Russian Federation Boulevard, P.O. Box 86, 12156 Phnom Penh, Cambodia
Panha Hok
Faculty of Hydrology and Water Resources Engineering, Institute of Technology of Cambodia, Russian Federation Boulevard, P.O. Box 86, 12156 Phnom Penh, Cambodia
Sarit Chung
Faculty of Hydrology and Water Resources Engineering, Institute of Technology of Cambodia, Russian Federation Boulevard, P.O. Box 86, 12156 Phnom Penh, Cambodia
Jorma Koponen
EIA Finland Ltd., Sinimäentie 10B, 02630 Espoo, Finland
Water and Development Research Group, Aalto University, Tietotie 1E, 02150 Espoo, Finland
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This preprint is open for discussion and under review for Natural Hazards and Earth System Sciences (NHESS).
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Droughts which impact precipitation, soil moisture and streamflow are more impactful than droughts affecting any one compartment separately. We perform the first global multi-model assessment of (simultaneously co-occurring) compound droughts. We find that compound droughts have become more widespread and more likely across 1961–2020 except for the boreal environments. The global models, however, have high uncertainty: there is a need for global models targeting droughts specifically.
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The relationship between environmental flow violations and freshwater biodiversity at a large scale is not well explored. This study intended to carry out an exploratory evaluation of this relationship at a large scale. While our results suggest that streamflow and EF may not be the only determinants of freshwater biodiversity at large scales, they do not preclude the existence of relationships at smaller scales or with more holistic EF methods or with other biodiversity data or metrics.
Vili Virkki, Elina Alanärä, Miina Porkka, Lauri Ahopelto, Tom Gleeson, Chinchu Mohan, Lan Wang-Erlandsson, Martina Flörke, Dieter Gerten, Simon N. Gosling, Naota Hanasaki, Hannes Müller Schmied, Niko Wanders, and Matti Kummu
Hydrol. Earth Syst. Sci., 26, 3315–3336, https://doi.org/10.5194/hess-26-3315-2022, https://doi.org/10.5194/hess-26-3315-2022, 2022
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Unsustainable sand mining poses a threat to the stability of river channels. We use satellite imagery to estimate volumes of material removed from the Mekong River, Cambodia, over the period 2016–2020. We demonstrate that current rates of extraction now exceed previous estimates for the entire Mekong Basin and significantly exceed the volume of sand naturally transported by the river. Our work highlights the importance of satellite imagery in monitoring sand mining activity over large areas.
Marko Kallio, Joseph H. A. Guillaume, Vili Virkki, Matti Kummu, and Kirsi Virrantaus
Geosci. Model Dev., 14, 5155–5181, https://doi.org/10.5194/gmd-14-5155-2021, https://doi.org/10.5194/gmd-14-5155-2021, 2021
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Different runoff and streamflow products are freely available but may come with unsuitable spatial units. On the other hand, starting a new modelling exercise may require considerable resources. Hydrostreamer improves the usability of existing runoff products, allowing runoff and streamflow estimates at the desired spatial units with minimal data requirements and intuitive workflow. The case study shows that Hydrostreamer performs well compared to benchmark products and observation data.
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Short summary
We studied the cumulative impact of future development and climate change scenarios on discharge and floods in the Cambodian Mekong floodplain. We found that hydropower impacts dominate, acting in opposition to climate change impacts to drastically increase dry season flows and reduce wet season flows even when considering the higher RCP8.5 level. The consequent reduction in flood extent and duration may reduce regional flood risk but may also have negative impacts on floodplain productivity.
We studied the cumulative impact of future development and climate change scenarios on discharge...
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