The truth about dams is dirty, and it’s a long list.
- Dams block rivers, and not just a river’s water but also its fish, sediment, and nutrients;
- Dams slow rivers which changes a river’s ecology, water temperature, sediment flow, and aquatic habitat;
- Dams always make a river’s water quality different, and usually make it worse;
- Dams can cause the extinction, and local extirpation, of fish and other forms of aquatic life. In fact, freshwater species are disappearing at a much faster rate than terrestrial or marine species across the planet;
- Dams harm, and often significantly reduce, riverine and local ecosystem biodiversity;
- Dams have flooded hundreds of millions of acres of land across the planet, destroying forests, drowning biodiversity, and causing the loss of carbon sequestration in now-flooded ecosystems;
- Dams can make river-bank and floodplain flooding worse;
- Dams exacerbate coastal flooding, beach erosion, and sea level rise.
If all of that is not bad enough, new science over the last few decades has proven that dams and reservoirs actually make climate change worse by emitting methane and other greenhouse gases. Sometimes these emissions for a hydropower dam can be as bad as that of a coal-fired powerplant.
That’s a big problem because we are in a race against the clock to tackle climate change, yet we aren’t currently measuring a critical emitter of methane, dams and reservoirs. Despite the science showing overwhelming evidence of the greenhouse gases caused by dams and reservoirs, many U.S. government agencies, as well as most of the hydropower industry, still deny the science.
As our country makes once in a lifetime investments in infrastructure, energy, water, and climate change resiliency, we all deserve to know that the climate impacts from dams and reservoirs are accounted for, and that our tax dollars are spent wisely. Simply stated, it is time to follow the science and tell the dam truth about all the negative impacts of dams.