Why We Need Dams — and a Sustainable Path Forward

This week CI staff are converging in Sweden at World Water Week, one of the biggest international water conferences. We’re speaking, organizing sessions and workshops, and meeting with decision-makers from all over the world. Much of the discussion is focused on dams — or, more correctly, water infrastructure.

Potential dam site, Beni River. Bolivia

Potential dam site on the Beni River in Bolivia. Although dams currently supply people all over the world with power, they can also have serious negative impacts on ecosystems. (© CI/photo by Bailey Evans)

Why? The simple reason is that we cannot talk about conservation or sustainable development without also talking about where to locate, how to build and how to operate dams.

As part of my current internship with CI and the Alliance for Global Water Adaptation, I have been spending many hours researching dams. It came as no surprise to find that the answers to the questions above are quite complex.

Traditionally, conservation groups simply said “no” to building dams due to their high environmental cost. Indeed, sedimentation, habitat loss and other side effects of dams have caused freshwater ecosystems and species to decline at a faster rate over the past century than any other category of ecosystem, including forests and oceans. In addition, dam construction has been responsible for the eviction of numerous indigenous and traditional communities from their homelands.

However, the strategy of fighting dam development hasn’t worked very well. With over 48,000 large dams exceeding 15 meters (over 49 feet) in operation worldwide, saying “no” to all dam construction is not a realistic solution.

Arguably, dams are one of the reasons that the United States and other developed nations have achieved so much economic success. Irrigation, farming, fishing, energy production, recreation and drinking water all depend on functioning dams. Meanwhile, large dams are being built at an incredible rate in developing countries, especially China and India; these countries also need regular water usage for cities, food and energy.

These numbers say it all:

  • The total number of dams globally is over 845,000 according to a Discover Magazine article.
  • The U.S. currently has 87,359 dams according to the U.S. Army Corps of Engineers National Inventory of Dams.
  • As of early 2013, China alone has more than 5,191 large dams over 15 meters high. Of those, over 117 massive dams greater than 60 meters (about 200 feet) have been completed or were under construction prior to 2006, according to Dr. Jia of the International Session of Hydropower.
  • The Mekong River in Southeast Asia is another area where pressure is increasing for additional, rapid dam development. On the Mekong there are several dozen dams newly in operation or under construction, and more than 85 new dams have been proposed. The massive Xayaburi Dam (the first of 12 dams proposed for the Lower Mekong) has served as a catalyst for more dam construction on the lower portion of the river. (Learn more about the status of dams on the Mekong in this March blog post.)

Rather than rejecting all dams outright, a better approach may be to ask, “When we need to build a dam, can we make it better for the environment?”

One study (PDF–3.92 MB) suggested that losses from droughts in countries such as Ethiopia reduced economic growth over more than a decade — effects we can mostly avoid or reduce in the U.S. by building dams in better locations or by more fairly distributing water. In fact, the construction of large dams has nearly stopped in the United States, reflecting new environmental regulations (such as the Endangered Species Act) and increased understanding about how much dams have affected our ecosystems.

woman in house near Gunung National Park, Indonesia

A hydroelectric dam recently brought electricity to families near Indonesia’s Gunung National Park who had been living off the grid for years. (© Jessica Scranton)

CI is working hard on multiple fronts to ensure that ecosystems and livelihoods are included in how governments, investors and companies think about dams and water management. Lina Barrera’s blog on managing shared water resources explains some of what CI is doing in the policy realm; Leonardo Sáenz’s recent post examined the connection between healthy cloud forests and dam productivity.

So where does that leave us? Until recently I wasn’t sure how to depict the best path forward. I have learned a good deal about climate adaptation in the short time I’ve been interning with CI and AGWA, but still couldn’t figure out how to sum up this piece.

Then I came across a presentation given by Casey Brown of the University of Massachusetts. He sums it up quite nicely by saying, “Decisions are deterministic, but water management is something that can be flexible and adaptable to our changing climate conditions. This involves monitoring (understanding the current state of a system), options (incorporating flexibility in the design), and decision support (using the appropriate information to respond to changes in a system).”

We need a process for decision-making in the face of climate uncertainty. Shifting weather patterns are predicted to greatly affect precipitation in many parts of the world. Some areas will become drier while others will see an increase in precipitation events. These changes will have untold consequences for the freshwater supply of the people living there. Decisions in water management planning must take this into account. After all, dams are built to last, but the times, they are a-changing.

For millennia, fresh water has connected species — including people — with their environment and each other. Examples are everywhere. On the African savanna, animals gather around water holes. Many major cities were built on the banks of rivers.

When it comes to development, water is also a connector, bringing together a vision of sustainable water management that includes species, livelihoods — even gender. Dams are just one piece of this puzzle, but they are a piece we can’t leave out.

Alex Mauroner is an intern in CI’s Center for Environment and Peace. His internship is supported by the Trott Foundation.


  1. Pingback: Why We Need Dams — and a Sustainable Path Forward | Human Nature – Conservation International Blog

  2. Noah says

    You rightly note that dams have displaced “numerous indigenous and traditional communities from their homelands”. Indeed, the World Commission on Dams estimates, conservatively, that 40-80 million people have been displaced by dams. Many millions more have been displaced or further impoverished due to the effects of dams on the natural resources that they use for their food, livelihoods and cultural practices. I appreciate your argument that we need to ask how we can bulid dams with minimal impact on the environment, and want to add that minimizing impacts on the poor, vulnerable communities that tend to live along rivers is imperative. Doing so in countries like China, India and Brazil will be a challenge.

  3. Willow Hill says

    When considering whether we need a new dam anywhere in the world, we may need to examine a cultural bias that says living off the grid is a bad thing. Simple, time-tested technologies have supported full, rich environmentally and culturally sustainable human lives of all our ancestors for generation after generation before the industrial revolution. How to reconcile this with what we have built and live with now — that’s a big question that I grapple with. I don’t expect quick answers, and yet, want to know these questions are being asked — If we bring third world people into the modern age with our technologies are we losing the chance to learn about theirs? Their ways that have endured, along with the planet, for a long long time? Are we really doing them a favor? If they looked past the immediate gain of having what the rest of the world has, and knew what the result may be — and it’s usually landlessness and urbanization — would they still choose modernization by this means (this is assuming they are given the choice)? I appreciate the thought you’ve given this, and know that together the many disciplines uniting thier efforts to solve big problems are doing the world a great service.

  4. Christer Borg says

    As president of River Savers Association in Sweden, with focus since 1974 mainly on hydro power and dams connected to HP, I think there is more than this article to think over. For instance the paper “The blue water footprint of electricity from hydropower”, 2011, Mekonnen and Hoekstra.

    Quote from that papers abstract:
    “The study assesses the blue water footprint of hydroelectricity – the water evaporated from man made reservoirs to produce electric energy – for 35 selected sites. The aggregated blue water footprint of the selected hydropower plants is 90Gm3 yr−1,which is equivalent to 10% of the blue water footprint of global crop production in the year 2000. The total blue water footprint of hydroelectric generation in the world must be considerably larger if one considers the fact that this study covers only 8% of the global installed hydroelectric capacity. Hydroelectric generation is thus a significant water consumer.”

    That means that you have to think twice, and perhaps more then that, if you feel a need for new dams for irrigation, then take in account that a lot of the fresh water will go up “as smoke” in the sky…

    And the fact that the world´s ENGO´s NO-argument has not been successful is more related to the unbalance in economic figures of promoting and advertising, then “bad” arguments.

    Christer Borg

  5. Peter Bosshard says

    Certainly, simply saying No to all dams is not the solution, but I am not aware of any NGOs that do this. We rather need to push for better decision-making processes that respect the rights of affected communities give social and environmental aspects the same weight as economic interests. The World Commission on Dams has presented a comprehensive framework for this.

    While we press for better decision-making processes, there are many destructive projects on critical ecosystems that should not go forward. They include the proposed dams on the Mekong mainstream and on many other rivers that are critical for sustaining ecosystems and livelihoods.

    We appreciate CI’s work on the importance of rivers for climate resilience. Support for the rights of affected communities (as espoused in the WCD framework) and for the struggle to stop the most destructive projects from going forward would also be welcome.

  6. Kaye says

    It’s a shame all the fossil fuel subsidies are not relocated to aerofarm technology and related water efficiency developments.

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