Building dams while respecting the environment

Research by Prof. Andrea Castelletti is awarded the Aspen Institute Italia 2021 Prize

A study on the strategic planning of dams in the Mekong basin has won the sixth Aspen Institute Italia Prize, awarded each year to a research project in the natural, theoretical or applied sciences, the result of a collaboration between scientists or research organisations in Italy and the United States. Among the authors of the study were Professor Andrea Castelletti of the Department of Electronics, Information and Bioengineering at the Politecnico di Milano, who was awarded the prize together with Rafael J.P. Schmitt (Standford University, Politecnico di Milano and University of California, Berkeley), Simone Bizzi (Politecnico di Milano and University of Padova) e G.Mathias Kondolf (University of California, Berkeley and University of Lyon).

Large dams are central to energy generation and agricultural irrigation in many countries around the world. At the same time, however, they alter the natural system of river processes, modifying hydrology, hindering sediment transport and damaging, sometimes irreparably, the ecological balance of the river, delta and riverbank populations. Research shows that strategic planning of dams can significantly reduce their impact on sediment transport without compromising energy generation and food production. This discovery was achieved by coupling a new mathematical model for assessing the large-scale impacts of dams with tools for multi-objective decision analysis.

The study was conducted on the Mekong River, where strong hydroelectric development is expected in the coming years. The current situation generates 54% of the planned hydropower, reducing the sand to the delta by 91% compared to a situation without dams. By adopting a strategic approach to planning when deciding where to build dams and of what size, it would have been possible to produce 68% of the planned energy while reducing sand transport by only 21%. The significance of these results opens up important areas for discussion in planning the 3,700 large dams that are awaiting construction around the world.

More information
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 Sustain1, 96–104 (2018).
The study online

Photo: Thomas Cristofoletti / Ruom