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World's Dams Unprepared for Climate Change Conditions

Dams have been designed for river flows that will soon no longer apply, according to new research
dams, hydropower, water, climate change, global warming



Noodle snacks/Wikimedia Commons

Over the past four years, John Matthews has been traveling the world to better understand freshwater and climate change issues. He found that poor planning is creating one of the biggest water-related threats.

"We need to think about managing water in a much more flexible way," said Matthews, who is director of fresh water and adaptation at Conservation International. "Let's not just design for a single future; let's think about multiple possible futures."

In a paper published this month in the journal PLoS Biology, Matthews and his co-authors argue that investment and management decisions risk exacerbating climate-initiated changes, which could lead to economic catastrophes.

The conventional method of building dams is fundamentally flawed, said Matthews. Looking at the available data, engineers decide on a flow rate that they feel will optimize the infrastructure project. The problem, says Matthews, is that historical data is not a very good guide to the future of freshwater resources -- particularly now that extreme water conditions have been exacerbated by a rapidly changing climate.

According to the United Nations, humans will feel the effects of climate change through the water supply. The hydrological cycle -- which includes surface and ground sources, glaciers, precipitation, runoff and vaporization -- is very sensitive to small climatic shifts. This is a concern not only because water is essential for subsistence, but because it's also the key to economic development. The way humans are managing water infrastructure and conservation, the authors argue, is only intensifying these issues.

Old dams, new realities
"It's not that we need to give up designing; it's that we need a better design and decisionmaking process," said Matthews. "We need to think carefully about how conditions may be shifting, because there are some things that we can say with high confidence are happening because of climate change."

Over the past century, dams made in the West have become more mismatched with their ambient climate. The Hoover Dam, for instance, was designed based on a 30-year period that had markedly higher precipitation levels than today. As a result of a decade of drought, the dam is now operating at only 30 percent of its capacity, said Matthews, and new mechanisms have been added to cope with the lower water levels.

When infrastructure plans are based on a set climate scenario, rather than a flexible one, it can be very costly in both human and economic terms, especially in the developing world, the paper argues.

Less-developed areas, particularly parts of East and South Asia, are now entering a period of rapid hydro infrastructure development. Since water managers are largely following the West's rigid planning model, these countries are going to have difficulty adapting to changes in water availability.

According to the Organisation for Economic Co-operation and Development, 40 percent of all development investments are at risk due to climate change, write authors in the PLoS paper. If a hydropower project fails to fulfill expectations due to the effects of climate change, governments could struggle to pay back loans from development investors.

New dams and power shortfalls
Masses of people could also face prolonged brownouts. Matthews saw this take place in Nepal, where low water levels rendered a brand-new dam project ineffective and cut off the water supply farther downstream.

"[Developing countries] are likely to make themselves poorer and make species and ecosystems decline at the same time, and I think that's a huge crisis," said Matthews.

The solution is to build new water infrastructure in stages, say the authors of the PLoS paper. Using that approach, managers can adjust their strategy as climate patterns become clearer. Another step is to integrate ecosystems into infrastructure development -- by "building with nature" rather than on top of it, using a system that will be more adaptive.

Finally, it's necessary to plan for multiple future climate scenarios by coordinating engineers, economists and conservationists. A collective approach will result in a more robust long-term strategy.

If water management practices stay the same and do not account for future risks, then "we're building things based on a hydrological lie," said Matthews.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

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