Water Resources Management

, Volume 26, Issue 12, pp 3495–3513 | Cite as

Downstream Hydrological Impacts of Hydropower Development in the Upper Mekong Basin

  • Timo A. Räsänen
  • Jorma Koponen
  • Hannu Lauri
  • Matti Kummu


The Mekong River Basin in Southeast Asia is experiencing extensive hydropower development. Concerns have been raised about the consequences of the development for the ecosystems, livelihoods and food security in the region. The largest planned hydropower dam cascade in the basin, the Lancang-Jiang cascade, is currently under construction and already partly built into the Upper Mekong Basin, China. In this paper we assess the impact of the Lancang-Jiang cascade on downstream hydrology by using a combination of a hydrological model and a reservoir cascade optimization model. The hydrological changes were quantified in detail at the Chiang Saen gauging station in Thailand, the first gauge station downstream from the cascade, and in lesser detail at four other downstream locations in the Mekong mainstream. We found that on average the Lancang-Jiang cascade increased the December–May discharge by 34–155 % and decreased the July–September discharge by 29–36 % at Chiang Saen. Furthermore, the Lancang-Jiang cascade reduced (increased) the range of hydrological variability during the wet season (dry season) months. The dry season hydrological changes were significant also in all downstream gauging stations, even as far as Kratie in Cambodia. Thus the Mekong’s hydrological regime has been significantly altered by the Lancang-Jiang cascade, but what the consequences are for ecosystems and livelihoods, needs further study.


Hydrological impact assessment Hydrological modelling Dynamic programming Hydropower operation The Mekong Basin Yunnan 



The authors would like to thank the Mekong River Commission for providing the discharge data for the study. The authors are grateful to Prof. Olli Varis, Dr. Marko Keskinen, Aura Salmivaara and Mirja Kattelus for their support. Timo Räsänen received funding from the RYM-TO Graduate School and Maa- ja Vesitekniikan Tuki ry. and Matti Kummu received funding from the postdoctoral funds of Aalto University. The research was also supported by Academy of Finland (project 133748).

Supplementary material

11269_2012_87_MOESM1_ESM.pdf (537 kb)
ESM 1 (PDF 536 KB)


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Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Timo A. Räsänen
    • 1
  • Jorma Koponen
    • 2
  • Hannu Lauri
    • 2
  • Matti Kummu
    • 1
  1. 1.Water & Development Research GroupAalto UniversityAaltoFinland
  2. 2.Environmental Impact Assessment Centre of Finland Ltd.EspooFinland

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