Hydrological changes in the Mekong River Basin - The effects of climate variability and hydropower development

Timo Räsänen

    Research output: ThesisDoctoral ThesisCollection of Articles


    The world's large rivers are increasingly exploited for human use and are affected by changes in global climate. Dams, the consumptive use of water and a changing climate have resulted in river fragmentation and flow alteration on a global scale. The Mekong River Basin has been one of the world's less affected large rivers, but recently the development has started to shape the river. In the Mekong, the livelihoods, the economy and food security are closely connected to the river environment and its productivity. The productivity in turn is largely driven by the hydrology. Therefore, an understanding of the ongoing hydrological changes is crucial. This dissertation aims at fulfilling hydrological research gaps in the Mekong. These research gaps concern the climate induced hydrological variability and the impact assessment of hydropower development in the Mekong. The main research framework of this dissertation is based on hydrology and water resources research and the methods are based on statistical and mathematical models. In addition, the dissertation discusses the role of disciplinarity in the hydrological knowledge production. The dissertation found that the Mekong's hydrology has been strongly influenced by El Niño – Southern Oscillation (ENSO), and that in recent decades the Mekong's hydrological variability has increased to levels that may not have been experienced within the past 700 years. The recent increase in hydrological variability was, at least partially, attributed to an increase in ENSO activity. The dissertation developed new assessment approaches for assessing hydropower development and found that river flows will be considerably affected and this development leads to increasing complexity and trade-offs among different sectors of society. In addition, it was found that climate variability and the development of the water resource infrastructure result in cumulative impacts that need further attention. Altogether, the dissertation concludes that the Mekong has entered a new hydrological era, where humans have become a major force transforming the Mekong's hydrology. The ongoing hydrological changes are likely to have an impact on ecology, livelihoods and food security. This new era requires new holistic planning and assessment processes, and in the case of hydrological and water resources research and education, the dissertation recommends the recognition of complexity, uncertainty, and co-operation across disciplines and societal sectors as future directions.
    Translated title of the contributionVesivoiman ja ilmastovaihteluiden aiheuttamat hydrologiset muutokset Mekong-joen valuma-alueella
    Original languageEnglish
    QualificationDoctor's degree
    Awarding Institution
    • Aalto University
    • Kummu, Matti, Supervising Professor
    • Varis, Olli, Thesis Advisor
    Print ISBNs978-952-60-5796-5
    Electronic ISBNs978-952-60-5797-2
    Publication statusPublished - 2014
    MoE publication typeG5 Doctoral dissertation (article)


    • Mekong
    • hydropower
    • climate variability
    • hydrological impact assessment


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