Hydropower Dams are Devastating to the Environment, Study Warns

A new study warns that countries constructing new hydroelectric dams should heed lessons from dams in the US and Europe in order to avoid serious environmental damage.

The research, which appears online this month at the “Proceedings of the National Academy of Sciences“, notes that hydropower in the US and Europe has been in decline for several decades now. Once considered a major salvation for clean, renewable energy, hydroelectric dams were the darling of the last century and reached their peak in the 1960s.

However, the shine quickly dulled when researchers and government officials began noticing that, while the dams could supply cheap energy, they came with a number of major environmental problems.

This latest study, done by researchers at Michigan State University, notes that dam creation slowed and virtually stopped in the US and Europe by the 1970s for two major reasons. Firstly, rivers are a finite resource, and those which could produce significant financial gains had already been dammed by that point. The second, and perhaps more pressing for us, is the extremely high environmental cost.

How Hydroelectric Dams Damage the Environment

Damming requires that we disturb the natural environment present in the rivers to begin with, including its aquatic life and ecology.

Dams impact how migratory fish can travel, either preventing them from reaching spawning grounds entirely or making it much harder for the fish to thrive. These operations also require some land clearing, including forest clearing, in order to create access for building the dam structures and then to allow for the infrastructure needed to keep the dams functioning. These two factors together mean that the biodiversity of these river environments is severely impacted by dam operations, and while we would expect some animal and plant life to bounce back, a portion will be lost.

In turn, this can result in agriculture and rural economies being disrupted and also deteriorating water quality, thanks to changes in the oxygen transfer going on in the rivers. This, in turn, will again impact the wildlife, of course.

One thing that may not be immediately obvious about hydroelectric dams is the amount of greenhouse gasses they actually put out. A study from 2016 found that the disruption to ecology in the rivers and surrounds creates an abundance of rotting vegetation. That leads to a billion tons of CO2 output every year.

It also creates a significant amount of methane release; in fact, scientists warned that we had been underestimating that release by about 25 percent. Methane is a super insulating gas with more warming power than CO2. Therefore, any large release of methane is a big problem if we want to keep global temperatures under control.

The report also notes some other problems with dams, namely that based on figures from Europe and the US, 90 percent of dams built since the 1930s have been more costly than initially predicted. That’s partly down to the fact that altering a river course can be unpredictable and the effects it can have on the surrounding land hard to predict. Also, hydroelectricity is dependent on an abundance of water.

So Why Does This Matter Now?

Given that Europe and the US have largely abandoned hydroelectric dams, we might wonder what the point of this study is, but it is raising these concerns for a reason: many developing economies are embracing hydroelectric power, and the environmental costs could be significant.

The BBC reports that in developing economies an estimated 3,700 dams are at various stages of development. Some of those will be large-scale projects, while others are much smaller-scale “micro” outfits in places like Romania that are being subsidized in large part by EU green tariffs.

Crucially though, evidence shows us that modern operations that were only recently completed or have reached near completion in places like Brazil, namely those spanning the Madeira river, have already cost far more than predicted, andhey could also have serious consequences for the local environment.

These are new dams, so this isn’t a product of decades-old inefficiency. Rather, it’s an issue with the hydroelectric power model itself.

What’s perhaps more discouraging is that many of these planned dams aren’t actually being used to supply energy to local people. Rather, they are being used by big businesses. Even if we ignore the environmental costs — which we do to our peril — it is hard to justify hydroelectric damming as being in the public interest.

“For hydropower to continue making a contribution to sustainable energy, it needs to consider from the outset the true costs – social, environmental and cultural – that may be involved,” Emilio Moran, John A. Hannah Distinguished Professor of Geography, Environment and Spatial Sciences at MU said in a press release. ”We also must consider costs in the pricing of the infrastructure, including the eventual removal of the dam, rather than pass those on to the public in 30 years.”

A More Sustainable Hydropower Future

The study is clear, however, that some dams can work and their overall output versus costs can be valuable, but to make hydroelectric dams a technology worth taking into our future energy strategy, the technology has to be overhauled.

For their part, the researchers say there are a number of new approaches in the works, but one that they cite in particular is instream turbine technology. These turbines do not require damming the river and so do not disturb the local vegetation and animal life in the same way. Unlike hydroelectric dams, which tend to be used by big businesses and not for energy grid generation for people, instream turbines can help local communities and, critically, would generally not need people living by rivers to be resettled.

Hydroelectric power may yet be able to help us fulfill our energy needs, but we need to overhaul it if we want to truly make hydropower a viable green energy option.

Photo credit: Getty Images.


Marie W
Marie W27 days ago


Daniel N
Past Member 4 months ago

Thank you for sharing

Peggy B
Peggy B6 months ago


Mark T
Mark T8 months ago


Shae L
Shae Lee8 months ago

Thank You for Sharing This !!!

Dr. Jan Hill
Dr. Jan Hill8 months ago


Paul B
Paul B8 months ago

Many of us feel the same way about other renewable energy sources like solar and wind. While they are attractive to the "clean energy" initiative, they can also be damaging to the environment, dead birds, other ground wildlife, and expense upgrades to the "system" by having to make special access for the lower amperage delivery of electricity, the peaks and valleys in production, etc.
In limited use it can work just fine but isn't that great, all the time.

Paul B
Paul B8 months ago

Oops, That was Ms. Snipes, not Snider.

S M8 months ago

And yet in Eastern Europe some politicians and bankers still consider building them! 😡

Tabot T
Tabot T8 months ago