Photo via Sandy Austin via Flickr CC
In the first ever global analysis of how dams impact food security and livelihoods, The Nature Conservancy and partners found that at least 472 million people have experienced the downside of dams. The new study goes beyond the displacement of people by new dam projects and into how communities living downstream from dams are negatively impacted by the changed water patterns, blocked movements of fish, floodplain grazing and other effects. Some of the findings are startling.
Published in a special issue of the Water Alternatives journal recognizing the 10th anniversary of the World Commission on Dams, the report used a database of documented dam effects on people from 120 rivers in 70 countries to create a geospatial analysis and case studies. Some of their findings include dramatic impacts, such as the total fish catch out of the Kafue River in Zambia dropped from consisting of 50% of three-spotted tilapia down to just 3%, and a 50% drop in the total fish catches on the Senegal River after dams were built.
In the Lower Mekong River alone, 40 million people depend on river and floodplain fisheries, and in the Sunderban Delta in Bagladesh, 73% of households are involved in floodplain fisheries. So the impacts of dam projects can be devastating to livelihoods.
"There are many places where dams have undeniably provided economic benefits such as flood protection, irrigation, and hydropower, but as this report shows they have also caused serious consequences for some of the world's most vulnerable people," said Brian Richter, The Nature Conservancy's Global Freshwater Program Director and lead author of the report. "At a time when global dam-building is rampant, we need to be smarter about planning for and operating dams in ways that alleviate harmful human and ecological impacts."
The authors illustrate in their report that there are solutions in both the planning phase as well as retroactively for dam projects to ensure that communities are not so badly affected. They point to such solutions as simple as evaluating the interactions between changing the structure of the ecosystem with economic developments and people's interactions with the river, then incorporating design features into the planning to avoid negative consequences, such as ensuring the dam will release enough water downstream to sustain species.
So often, dam projects are built with only the immediate rewards in sight. While dam projects are a boon for hydro power and managing water sources, major problems with dams include the displacement of people from their homes, such as is occurring with the Belo Monte dam; over abundance of dam projects, such as China's plans for the Yangtze River; and major changes to ecosystems downstream that imperil wildlife and - thanks to this report detailing it - communities and economies. Though this report lays out basic solutions to minimizing damage, it's still up to governments and engineers to take them into account. That's where the real difficulties begin.
The report, entitled "Lost in Development's Shadow: The Downstream Consequences of Dams" can be downloaded from Water Alternatives.
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