Every person requires access to fresh water to survive. Beyond our direct need for drinking water, water is critical to the global food supply and is an increasingly important part of our energy needs. To serve these multiple demands, there are more than 45,000 large dams and an exponentially larger number of smaller dams and other structures around the world.

Altered Rivers For Human Needs

These facilities and associated extractive uses of water have altered over 60 percent of the world?s major rivers. Around the world, government officials, development agencies, and industry leaders are proposing and building new dams to meet growing human demands. In fact, nearly 400 new dams are planned or under construction in Central America, 200 in Brazil, and in China, nearly 50 in the Yangtze River basin alone. 

Dams and large diversions and water withdrawals

• block the pathways used by migrating fish,
• reduce and rearrange the patterns of flowing water that have choreographed aquatic life cycles for millennia, and
• change water quality.

In addition to their effects on freshwater ecosystems, the construction of these projects affect terrestrial ecosystems locally and their operations can even affect nearshore coastal systems. As the health of the world?s freshwater ecosystems have declined, so too have their ability to support both biodiversity and human needs. 

These changes can have significant effects on the social fabric and economic well-being of affected people and communities, particularly among those whose livelihoods are still closely connected to nature.

Engaging Decision Makers to Minimize Impacts

The Nature Conservancy does not advocate the building of dams or other large water-related infrastructure projects. However, we recognize that despite the threats they pose to natural systems, more dams and diversions will be built to meet humanity?s needs. 

Because this development poses significant risks to the world?s freshwater ecosystems, the Conservancy believes that it is important to engage with those responsible for this growth in an effort to minimize the environmental and social threats posed by these projects. Through this engagement, we can help ensure that new dams and large diversions and water withdrawals are located, built and operated in ways that promote a more sustainable future for freshwater ecosystems and the people who depend upon those systems. 

The Nature Conservancy has an important role to play in helping mitigate some of the threats posed by dams and large water development projects. We seek to:

• steer new infrastructure away from places that have the most value for biodiversity and for local communities;
• provide information to government agencies and water managers about how these projects impact ecosystems and communities so that they can better understand the tradeoffs associated with each project; and
• where new projects are going forward, provide guidance to the responsible parties to help them design and operate dams in ways that minimize negative environmental impacts. 

In short, we seek to work with all relevant parties to find ways in which water can be better managed for people and nature.

Solutions Based on Science

To inform our efforts, we draw from our strategic analysis of global conservation priorities, our broad experience in developing solutions to conservation challenges, and our leadership in river science and water policy. 

Each opportunity requires collaborating with scientific experts and community members, facilitating discussion, and building bridges between ecology and engineering. This work is often technically challenging and politically sensitive. However, we believe that it must be pursued if we are going to have a future with healthy rivers capable of supporting both biodiversity and human needs. 

Ultimately, our success as an organization will be measured not by our own deeds but by the actions of others, including dam builders and operators, who integrate ecosystem health considerations into planning and decision making.

Nature picture credits (top to bottom, left to right): Photo © Scott Warren (Itaipu hydroelectric Dam, Brazil); Photo © Mark Godfrey/The Nature Conservancy (Downriver view from"La Punilla", site of a proposed dam on the Nuble river).