Unprecedented wave of new dams could spell disaster far beyond Laos

By Stuart Orr, Freshwater Practice Leader, WWF

© Hartmut Jungius / WWF

The scale of the catastrophe in Laos is still unclear. Dozens could be dead, killed by the man-made flash floods that swept through their villages after the collapse of a dam under construction in Attapeu province in southern Laos. Thousands are homeless, their villages and livelihoods destroyed. It is a tragic reminder of the inherent risks of major dam projects — just as the world finds itself in the middle of a headlong rush for hydropower as countries seek to produce extra energy while reducing carbon emissions.

From the Amazon to Zambia, thousands of new hydropower projects are under construction or on the drawing board. Maps show rivers across the Balkans and Himalayas smothered in planned dams. Governments and developers talk excitedly about the energy that could be generated, the jobs created. Meanwhile, risks and costs are invariably downplayed, and community and environmental concerns often disregarded — give or take the usual rhetoric about ‘consultation and impact mitigation’.

The reality is that major dam projects require not only advanced engineering expertise but also good governance to ensure that the best construction practices are followed and that governments opt for the best trade-offs between benefit and risk. But this latest disaster once again raises some serious questions, particularly about the capacity of small developing countries to effectively oversee the development of numerous hydropower projects — often at breakneck speed.

Laos currently has dozens of hydropower dams under construction, with many more awaiting the green light. It is questionable whether the country has the institutional capacity to fully review all the various feasibility studies and environmental impact assessments as well as monitor all the ongoing construction work — the same is true of other countries in this new dam-rush era.

All this heightens the risks that are part and parcel of every major hydropower project. While dam collapses are the most catastrophic in the short term, large dams involve a variety of other risks that can negatively impact people and nature from local communities to distant deltas. Many of those risks are specific to each river and each site, and they are all cumulative, requiring well-coordinated multi-disciplinary teams to assess them fully. As a result, these risks are very seldom fully factored into the ‘should-we-build-it-or-not’ equation.

Take the world’s forgotten fish — freshwater fish. At least 11.5 million tonnes of wild freshwater fish are caught each year, providing low-cost protein to tens of millions of people and enhancing food security. But major dams block fish migration routes, preventing species from reaching their spawning grounds and devastating wild fish stocks. The lower Mekong river boasts the world’s most productive freshwater fisheries but dams in upstream countries — including Laos and Cambodia — have already contributed to their decline. Future dams could see populations and catches collapse, threatening the livelihoods of millions.

This is a far less visible risk, but a very real one in the Mekong — and many other river basins around the world where communities rely on fish stocks that depend on free flowing rivers.

And then there are the world’s sinking and shrinking deltas. While everyone is aware of the risk of rising seas, very few seem to know that deltas around the world are already disappearing — bit by bit. Or by one and half football fields per day in the case of the Mekong and one football field per hour in the case of the Mississippi. The cause — not enough sediment is flowing down rivers to replenish the deltas because sand and silt are being blocked by dams. This is putting not only the future of many people (500 million people live in major Asian deltas alone) but also some of the world’s most productive agricultural land at risk.

Already we are watching houses and infrastructure gobbled up by the sea — and that’s before it really starts to rise.

Factor in associated risks like river bank erosion and the displacement of communities and it’s clear that every dam involves significant impacts and trade-offs, which are only magnified by the cumulative impact of a series of dams. This is why it is absolutely critical for countries to pursue a system-wide approach to dam development — as part of an overall sustainable energy plan. Otherwise dams around the world could spell further disaster for people and nature.

Hydropower has an important role to play in providing reliable, renewable power in countries, like Laos, where so many people lack basic access to electricity. But new dams — and even those under construction — need to be thoroughly and transparently assessed in terms of all costs and benefits. And very carefully sited — off mainstems, for example — to mitigate the considerable impacts downstream.

Most importantly, hydropower dams need to be looked at again in the light of the plunging cost of solar and wind energy and large-scale storage. These now provide a genuine alternative to major hydropower projects — beset as they so often are with social, environmental and financial risk. Solar, in particular, is becoming much more competitive, is much less capital intensive, and can be implemented in a much shorter timeframe. It also carries far less risks.

When was the last time you heard about a solar power plant disaster?

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