A massive push has seen hydropower projects cropping up all over the African continent. Touted as a way of producing lots of cheap green energy for developing nations, they’re often met with controversy. From the eviction of tribal communities from their ancestral lands to doubts about their eco-friendly credentials, a new study has picked up another issue to add to the list. Researchers have found that living next to a dam in sub-Saharan Africa could increase one's risk of contracting malaria.

“Dams are at the center of much development planning in Africa. While dams clearly bring many benefits – contributing to economic growth, poverty alleviation and food security – adverse malaria impacts need to be addressed or they will undermine the sustainability of Africa's drive for development,” says Solomon Kibret, lead author of the paper published in Malaria Journal. In fact, the researchers estimate that 1.1 million cases of malaria annually can be directly linked to the presence of dams. 

There are currently 1,268 dams already in place in sub-Saharan Africa, spread right across the region – from the Gambia in the West to Sudan in the East. Out of these, the researchers calculated that just under two-thirds are located in malarious areas. They then compared the incidence of malaria in communities within 5 kilometers (3 miles) of a dam with communities further away. They found that around 15 million people living near dams were at risk, and over 1 million malaria cases annually were linked to the presence of dams.  

By increasing the amount of standing freshwater, the dams – and specifically the reservoirs they create – form an ideal breeding ground for the mosquito larvae. This leads to an increase in the number of the insects, and thus the chances that someone will be bitten and infected by malaria.

The researchers say that while the number of those infected is a tiny proportion of the 207 million cases reported globally, they shouldn’t be the ones who have to suffer the consequences of these new developments. With a further 78 dams planned to be built over the next few years, it is argued that the construction companies should be made to shoulder the cost for anti-malaria programs in surrounding villages, rather than countries having to find the money from already overstretched public health organizations.

“Dams are an important option for governments anxious to develop,” says Matthew McCartney from the International Water Management Institute and a co-author of the paper. “But it is unethical that people living close to them pay the price of that development through increased suffering and, possibly in extreme cases, loss of life due to disease.”