‘Grey infrastructure’ can’t meet future water storage needs

Photo: Aerial view of the Saint Etienne Cantales hydroelectric dam in France. | Romain Longieras

A new study maps how energy and food systems depend on stored water to generate hydropower and feed irrigation. Dams and reservoirs won’t be able to meet the demand in coming decades.

As demand for food and energy grows, water will only become more precious. A new Stanford-led study provides a first-of-its-kind global overview of the role dams and reservoirs play in providing water storage, revealing so-called grey infrastructure won’t be enough to meet future demands for hydropower and agricultural irrigation. The analysis, published this week in Renewable and Sustainable Energy Reviews, underscores the necessity of exploring demand- and supply-side alternatives, such as other renewable energy sources and nature-based approaches for water storage.

The study forecasts the global need for stored irrigation water will grow by about 70% – enough to cover an area the size of California under nearly two feet of water.

“Water storage is a critical and globally limited resource,” said study lead author Rafael Schmitt, a lead scientist at the Stanford-based Natural Capital Project. “Our study shows that the solutions of the past are insufficient, and can be damaging to already overstretched freshwater ecosystems.” 

Making better infrastructure decisions

Dams and reservoirs fuel hydropower, store water for irrigation, provide drinking water, and lower flood risks. They also inflict ecological and societal damage by disrupting fish migrations and displacing people and terrestrial ecosystems, among other impacts. To help policymakers make more informed decisions about grey infrastructure and alternatives, Schmitt and co-author Lorenzo Rosa, a principal investigator at Carnegie Science and an assistant professor (by courtesy) of Earth system science in the Stanford Doerr School of Sustainability, trained their focus on crucial gaps in our understanding of how dams and reservoirs contribute to food and energy security.

Our study by no means advocates for building more dams. What we urgently need is a global debate about how to meet water storage needs for critical sectors.

Rafael Schmitt
Lead scientist, Stanford Natural Capital Project

The researchers used machine learning to quantify the multipurpose roles of the world’s 6,000 largest dams and reservoirs. The analysis revealed that dammed reservoirs globally store about 1,000 times the volume of California’s largest man-made lake, Shasta Lake. Of that, less than 5% reaches irrigated crops. The dams analyzed provide 505 gigawatts of hydropower, 40% of current total global hydropower capacity, according to the study. Worldwide, about 3,700 dams have been identified for potential development. If all of them were constructed, they could provide about 60% more energy and about 40% more […]

Full article: news.stanford.edu