260,000 km of rivers could be impacted by hydro dams

Over 260,000 kilometres of river could potentially be at risk due to proposed hydro dams, according to researchers at McGill University. 

Using a dataset of more than 3,700 potential hydropower projects, the researchers calculated their impacts on rivers worldwide. 

The researchers found that the Amazon, the Congo and the Irrawaddy are just a few of the rivers that are at risk of losing their free-flowing status if the construction takes place. 

The authors of the study highlight that connected and healthy rivers deliver diverse benefits that are often overlooked.

For example, freshwater fish stocks improve food security, the delivery of sediments nourish agriculture and keep deltas above rising sea sand floodplains help to mitigate the impacts of flooding and support a wealth of biodiversity. 

Moreover, the researchers also found that all the proposed dams would collectively generate less than 2% of the renewable energy needed by 2050. 

Günther Grill, a post-doctoral fellow at McGill said: ‘It is true that hydropower is a source of renewable energy with relatively low carbon emissions. However, hydropower projects can permanently and irreversibly impact rivers and floodplain dynamics and functions, often in tropical wilderness areas with high biodiversity.’

Michele Thieme, a lead freshwater scientist at World Wildlife Fund (WWF) and lead author of the study added: ‘When it comes to river health, climate change and biodiversity loss, we can no longer afford to think of these as separate issues.

‘Rivers are powerful agents for keeping wildlife and communities healthy, especially in a warming climate, yet their ability to support life is threatened by hydropower dams in many parts of the world. The best policy solutions will be those that balance renewable energy needs with the many benefits of thriving freshwater ecosystems.

‘There has been a long history of conflicts, studies, and debate over how to both protect rivers and develop them sustainably.

‘With a pause in new developments caused by the global pandemic, anticipated further implementation of the Paris Agreement and high-level global climate and biodiversity meetings in 2021, now is an opportune moment to consider the current trajectory of development and policy options for reconciling dams with freshwater system health.’

Photo by Joshua Sukoff