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ABSTRACT Dams in the Mekong Basin are mostly planned project-by-project and without strategic analysis of their cumulative impacts on river processes such as sediment connectivity. We

analyse missed and future opportunities for reducing hydropower impacts on sediment connectivity through strategic planning of dams in the Se Kong, Se San and Sre Pok (‘3S’) tributaries of

the lower Mekong, which are critically important as a source of sand for the Mekong Delta. With strategic planning, 68% of the hydropower potential of the 3S Basin could have been developed

while trapping 21% of the basin’s sand load. The current dam portfolio resulting from project-by-project planning uses 54% of the hydropower potential while trapping 91% of the sand load.

Results from the 3S demonstrate that strategic network-scale planning is crucial for developing lower-impact hydropower, a relevant finding given the at least 3,700 major dams that are

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Earth Surf._ _Zenodo._ https://doi.org/10.5281/zenodo.824854 (2017). Download references ACKNOWLEDGEMENTS During this research, R.J.P.S. was supported by a grant from the UC Berkeley

Institute of International Studies supporting the interdisciplinary faculty seminar Water Management: Past and Future Adaptations, and a PhD scholarship of the German National Academic

Foundation. This research was partially supported through the EU Horizon 2020 Project AMBER (grant agreement 689682). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Natural Capital Project,

Department of Biology and the Woods Institute for the Environment, Stanford University, Stanford, CA, USA R. J. P. Schmitt * Department of Electronics, Information, and Bioengineering,

Politecnico di Milano, Milano, Italy R. J. P. Schmitt, S. Bizzi & A. Castelletti * Department of Landscape Architecture and Environmental Planning, University of California, Berkeley,

CA, USA R. J. P. Schmitt & G. M. Kondolf * Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland A. Castelletti * Collegium–Lyon Institute for Advanced Study,

University of Lyon, Lyon, France G. M. Kondolf Authors * R. J. P. Schmitt View author publications You can also search for this author inPubMed Google Scholar * S. Bizzi View author

publications You can also search for this author inPubMed Google Scholar * A. Castelletti View author publications You can also search for this author inPubMed Google Scholar * G. M. Kondolf

View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS R.J.P.S., S.B., A.C. and G.M.K. designed the research and developed the paper. R.J.P.S.

and S.B. developed experiments and analysed data. R.J.P.S. performed numerical experiments and designed visual elements. CORRESPONDING AUTHOR Correspondence to R. J. P. Schmitt. ADDITIONAL

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permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Schmitt, R.J.P., Bizzi, S., Castelletti, A. _et al._ Improved trade-offs of hydropower and sand connectivity by strategic dam planning in the

Mekong. _Nat Sustain_ 1, 96–104 (2018). https://doi.org/10.1038/s41893-018-0022-3 Download citation * Received: 21 September 2017 * Accepted: 11 January 2018 * Published: 09 February 2018 *

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