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 proposed worldwide.
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
State of the Basin Report 2010 (Mekong River Commission, 2010).
Ziv, G., Baran, E., Nam, S., Rodríguez-Iturbe, I. & Levin, S. A. Trading-off fish biodiversity, food security, and hydropower in the Mekong River Basin. Proc. Natl Acad. Sci. USA 109, 5609–5614 (2012).
Winemiller, K. O. et al. Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong. Science 351, 128–129 (2016).
World Energy Outlook Special Report on Southeast Asia 2015 (International Energy Agency, 2015).
Kummu, M., Lu, X. X., Wang, J. J. & Varis, O. Basin-wide sediment trapping efficiency of emerging reservoirs along the Mekong. Geomorphology 119, 181–197 (2010).
Kondolf, G. M., Rubin, Z. K. & Minear, J. T. Dams on the Mekong: cumulative sediment starvation. Water Resour. Res. 50, 5158–5169 (2014).
Rubin, Z. K., Kondolf, G. M. & Carling, P. A. Anticipated geomorphic impacts from Mekong basin dam construction. Int. J. River Basin Manag. 13, 105–121 (2015).
Schmitt, R. J. P., Rubin, Z. & Kondolf, G. M. Losing ground—scenarios of land loss as consequence of shifting sediment budgets in the Mekong Delta. Geomorphology 294, 8–69 (2017).
Merritt, W. S., Letcher, R. A. & Jakeman, A. J. A review of erosion and sediment transport models. Environ. Modell. Softw. 18, 761–799 (2003).
Bracken, L. J., Turnbull, L., Wainwright, J. & Bogaart, P. Sediment connectivity: a framework for understanding sediment transfer at multiple scales. Earth Surf. Process. Landf. 40, 177–188 (2015).
Heckmann, T., Schwanghart, W. & Phillips, J. D. Graph theory—recent developments of its application in geomorphology. Geomorphology 243, 130–146 (2015).
Czuba, J. A. & Foufoula-Georgiou, E. A network-based framework for identifying potential synchronizations and amplifications of sediment delivery in river basins. Water Resour. Res. 50, 3826–3851 (2014).
Schmitt, R. J. P., Bizzi, S. & Castelletti, A. Tracking multiple sediment cascades at the river network scale identifies controls and emerging patterns of sediment connectivity. Water Resour. Res. 52, 3941–3965 (2016).
Kondolf, G. M. et al. Changing sediment budget of the Mekong: cumulative threats and management strategies for a large river basin. Sci. Total. Environ. 625, 114–134 (2018).
Bravard, J.-P., Goichot, M. & Gaillot, S. Geography of sand and gravel mining in the lower Mekong River. EchoGéo. https://doi.org/10.4000/echogeo.13659 (2013).
Bravard, J.-P., Goichot, M. & Tronchère, H. An assessment of sediment-transport processes in the lower Mekong River based on deposit grain sizes, the CM technique and flow-energy data. Geomorphology 207, 174–189 (2014).
Opperman, J. J., Grill, G. & Hartmann, J. The Power of Rivers: Finding Balance Between Energy and Conservation in Hydropower Development (The Nature Conservancy, 2015).
Jager, H. I., Efroymson, R. A., Opperman, J. J. & Kelly, M. R. Spatial design principles for sustainable hydropower development in river basins. Renew. Sustain. Energy Rev. 45, 808–816 (2015).
Opperman, J. J. et al. The Power of Rivers: A Business Case (The Nature Conservancy, 2017).
Schmitt, R. J. P., Bizzi, S., Castelletti, A. & Kondolf, G. M. Stochastic modeling of sediment connectivity for reconstructing sand fluxes and origins in the unmonitored Se Kong, Se San, and Sre Pok tributaries of the Mekong River. J. Geophys. Res. https://doi.org/10.1002/2016JF004105 (2017).
Hydropower Project Database (Mekong River Commission, 2012).
Ansar, A., Flyvbjerg, B., Budzier, A. & Lunn, D. Should we build more large dams? The actual costs of hydropower megaproject development. Energy Policy 69, 43–56 (2014).
The World Bank: Countries and Economies (World Bank, accessed 19 July 2017); http://data.worldbank.org/country/
Wild, T. B. & Loucks, D. P. Managing flow, sediment, and hydropower regimes in the Sre Pok, Se San, and Se Kong Rivers of the Mekong basin. Water Resour. Res. 50, 5141–5157 (2014).
Kondolf, G. M. et al. Sustainable sediment management in reservoirs and regulated rivers: experiences from five continents. Earth’s Future 2, 256–280 (2014).
Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L. & Tockner, K. A global boom in hydropower dam construction. Aquat. Sci. 77, 161–170 (2014).
SRTM 90m Digital Elevation Database v4.1 (CGIAR-CSI, 2008).
Piman, T., Cochrane, T. A., Arias, M. E., Green, A. & Dat, N. D. Assessment of flow changes from hydropower development and operations in Sekong, Sesan, and Srepok Rivers of the Mekong Basin. J. Water Resour. Plann. Manag. 139, 723–732 (2013).
Engelund, F. & Hansen, E. A Monograph on Sediment Transport in Alluvial Streams (Tekniskforlag Skelbrekgade 4, Copenhagen, 1967).
Gran, K. B. & Czuba, J. A. Sediment pulse evolution and the role of network structure. Geomorphology. https://doi.org/10.1016/j.geomorph.2015.12.015 (2015).
Czuba, J. A., Foufoula‐Georgiou, E., Gran, K. B., Belmont, P. & Wilcock, P. R. Interplay between spatially explicit sediment sourcing, hierarchical river‐network structure, and in‐channel bed material sediment transport and storage dynamics. J. Geophys. Res. https://doi.org/10.1002/2016JF003965 (2017).
Koehnken, L. Discharge and Sediment Monitoring Program—Program Review and Data Analysis. Part 1: Program Review and Recommendations (Mekong River Commission, 2012).
Koehnken, L. IKMP Discharge and Sediment Monitoring Program Review, Recommendations and Data Analysis. Part 2: Data Analysis of Preliminary Results (Mekong River Commission, 2012).
Lisenby, P. E. & Fryirs, K. A. ‘Out with the Old?’ Why coarse spatial datasets are still useful for catchments-scale investigations of sediment (dis)connectivity. Earth Surf. Process. Landf. 42, 1588–1596 (2017).
Schwanghart, W. & Scherler, D. Bumps in river profiles: the good, the bad, and the ugly. Earth Surf. Dynam. 5, 821–839 (2017).
Pereira, J. F., McCorquodale, J. A., Meselhe, E. A., Georgiou, I. Y. & Allison, M. A. Numerical simulation of bed material transport in the lower Mississippi River. J. Coast. Res. 56, 1449–1453 (2009).
Dang, T. A. & Tran, T. H. Application of the Mike21C model to simulate flow in the lower Mekong River Basin. Springerplus 5, 1982 (2016).
Development of Guidelines for Hydropower Environmental Impact Mitigation and Risk Management in the Lower Mekong Mainstream and Tributaries (Mekong River Commission, 2016).
Stevens, H. H. Jr & Yang, C. T. Summary and Use of Selected Fluvial Sediment-Discharge Formulas Water Resources Investigations Report; 89–4026 (US Geological Survey, 1989).
Minear, J. T. & Kondolf, G. M. Estimating reservoir sedimentation rates at large spatial and temporal scales: a case study of California. Water Resour. Res. 45, W12502 (2009).
Brown, C. B. Discussion of sedimentation in reservoirs. Proc. Am. Soc. Civil. Eng. 69, 1493–1500 (1943).
Brune, G. M. Trap efficiency of reservoirs. Eos Trans. Am. Geophys. Un. 34, 407–418 (1953).
Burneikis, J., Streimikiene, D. & Punys, P. in Hydropower in the New Millennium: Proc 4th Int. Conf. Hydropower (eds. Honningsvag, B. et al.) 11–17 (CRC, Boca Raton, 2001).
Power System Development Plan for Lao PDR. Final Report. Vol. A: Main Report (World Bank, 2004).
Power System Development Plan for Lao PDR. Final Report. Vol. C: Project Catalogue (World Bank, 2004).
Schmitt, R. J. P., Bizzi, S., Castelletti, A. & Kondolf, G. M. Stochastic modeling of sediment connectivity for reconstructing sand fluxes and origins in the unmonitored Se Kong, Se San, and Sre Pok tributaries of the Mekong River [Data set]. J. Geophys. Res. Earth Surf. Zenodo. https://doi.org/10.5281/zenodo.824854 (2017).
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).
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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
Nature Sustainability (2021)
Scientific Reports (2020)
Nature Sustainability (2020)
Nature Communications (2019)