Although dams provide many benefits to society, they can significantly fragment rivers and alter their flows. These changes can harm river ecosystems, reduce fish populations and negatively affect the economic well-being of local communities. Two-thirds of the world's rivers have already been significantly altered by dams – and, in part due to growing concerns about climate change, thousands of new hydropower dams are being planned and built around the planet.

To ensure that this expansion of hydropower unfolds in a manner that is consistent with healthy river basins, the Conservancy is promoting a set of tools and approaches, collectively called “Hydropower by Design” to promote more sustainable planning and operation of hydropower dams.

Hydropower by Design emphasizes a central principle: Truly sustainable hydropower can be evaluated and implemented only across large geographic areas, such as a major river basin or region. 

Key features of Hydropower by Design include:

1. Develop a conservation blueprint or environmental flow standards for a large geographic area, such as a region or river basin.
2. Improve the design and operation of existing and planned dams.
3. Integrate information from above steps into the planning, review, and licensing of new and existing dams.

Case studies

1. Patuca River, Honduras
2. Yangtze River
3. Penobscot River