The healthiest rivers are those that flow freely, beginning from springs and seeps or from snow fields high in the mountains, meandering across floodplains, connecting fish and other species to a wide variety of diverse habitats, changing character by season, and proceeding unimpeded to their ultimate destination (usually the ocean).

Dams and other obstructions fundamentally inhibit rivers from functioning properly. Dams remove water from rivers for electricity generation, domestic and industrial water supply, irrigation, and flood damage reduction. They change the flow characteristics that species and ecosystem processes depend upon, often eliminating triggers for reproduction and growth. And they block the movement of fish and other aquatic species, sediment, and nutrients. Water trapped behind dams in reservoirs and man-made lakes moves slower, has different water temperature and chemistry, and results in reduced species variety and increased risk of predators. Water trapped behind dams also generates evaporative losses, particularly in hot and dry areas. Other infrastructure (diversions, channel armoring, etc.) alter habitat and processes, too.

Most dams in the U.S. are privately owned, but the bigger dams tend to be operated by the U.S. Army Corps of Engineers, Bureau of Reclamation, and other energy production and water management authorities. Understanding a dam’s purpose(s), applicable laws, and relevant regulatory framework can help define opportunities to stop, remove or change the operation of dams and improve the health of our rivers.

Get informed, learn whether there is a dam on your river and who operates it, and explore what you can do to make a difference. Knowing your goals from a water quantity perspective (what volume of water within what range should be released at a particular time of the year, for how long, and reduced or increased at what rate of change) can help you become a more effective advocate for your waters.

If tackling dam removal, reoperation, or opposition is not realistic for you either due to capacity, priorities, or other variables, consider opportunities to replace gray infrastructure with green infrastructure to restore natural processes and function.

Learn more:

• Dam Removal Resource Center by American Rivers
• FERC Relicensing Process by American Whitewater
• Resources about hydropower by Hydropower Reform Coalition
• Environmental flows at US Army Corps of Engineers dams by The Nature Conservancy
• Damnation
• EPA Resource: Frequently Asked Questions on the Removal of Obsolete Dams