CONTEXT:

The Inga 3 dam has long been planned on the Congo River, the world’s second-largest river by volume, and recently found to be the world’s deepest river. The river is unique in that it has large rapids and waterfalls very close to the mouth while most rivers have these features upstream. The river’s powerful rapids at the Inga site are said to possess the largest hydropower potential in the world, which has for decades attracted dam planners who have dreamed of harnessing the mighty Congo’s power.

PROJECT IMPACTS:

The Congo River nourishes immense biodiversity: It’s home to at least 700 fish species, and it supports the world’s second-largest rainforest. It also empties its vast sediment load into one of the largest carbon sinks in the world, the Congo Plume in the Atlantic. The incredible velocity at the Inga site likewise makes it a hotspot for extremely rare endemic freshwater species that have only recently begun to be studied and documented. 

 

The Congo River sustains mangrove forests at its mouth which are rich in biodiversity and protected by a national park. The mangrove islands are home to manatee populations and other endangered species, and to several villages. Mangroves help protect coastal areas from the ravages of large storms, and are highly vulnerable to impacts from damming.

 

In addition to riverine biodiversity, the planned dams will affect the habitats of endangered chimpanzees, vulnerable hippopotamus and other mammal populations. Beyond impacts near and downstream of the Inga site, the project’s footprint would potentially be enormous, with very little known about the routing of the transmissions lines and the impacts they would have on communities, wildlife, and protected areas along the way.

Biodiversity Snapshot

IUCN red list species & status: 146 fish species identified in the Inga rapids area, with many more species not having been identified or studied. The Lower Congo is host to a unique array of freshwater species, 30% of which are endemic.

ENDANGERED

Chimpanzee

VULNERABLE

Hippopotamus

The unique biodiversity of the Lower Congo

The extreme and varied conditions of the Lower Congo have produced a number of rare and unusual endemic species, including recently identified sightless fish that inhabit the depths of the Congo River. These bottom dwellers live over 100 meters below the surface, habitats created by the river’s enormous power. The river is so turbulent that fish have been documented suffering decompression sickness (the “bends”) from surfacing at great speed by force of the currents.

Indeed, these currents have been shown to have effectively created numerous isolated habitats within the same stretch of river, each inhabited by different species. The conditions in the Lower Congo have also led to research into concurrent evolution, where fish species otherwise extremely different from one another - for example cichlids and catfish - have evolved similar characteristics such as depigmentation.

AT-RISK SPECIES PROFILE

PROJECT IMPACTS

LESSONS

INGA 3

Democratic Republic of Congo

​​Dam would impact biodiverse stretch of rapids and block sediments that are essential to maintaining the Atlantic Congo plume, one of the world’s largest carbon sinks

Boatman on the Congo River

Image by International Rivers

Inga Dam

Image by International Rivers

Inga Site

Image by International Rivers

Biodiversity Snapshot

IUCN red list species & status: 146 fish species identified in the Inga rapids area, with many more species not having been identified or studied. The Lower Congo is host to a unique array of freshwater species, 30% of which are endemic.

ENDANGERED

Chimpanzee

VULNERABLE

Hippopotamus

Company: China Three Gorges

Impact Category

Great Apes

Impact Category

Biodiversity Hotspot

CAPACITY

4.8 or 11 GW

COST

$14-$18 billion​

STATUS

Proposed

1.

Sufficient resources need to be allocated to studying the biodiversity present at the Inga rapids and mitigating identified impacts.

2.

Transmission lines route should be determined based on rigorous study of options to minimize impacts on wildlife, protected areas, and human populations.

3.

The suite of environmental and impact studies should be comprehensive and adequately resourced and take into account a full cumulative impact assessment of existing and planned hydropower development at the Inga site.