'Hacking nature': Africa's most ambitious river and lake projects - some are out of this world

The Inga Dam on the Congo gets all the attention, but there are other even more daring ideas

SOME of Africa’s richest natural resources are its rivers and lakes, and over the years, there have been many proposed projects to harness the continent’s immense water resources.

One of the most talked-about is the Grand Inga Dam project in the DR Congo, first proposed over 50 years ago. Inga is at the mouth of the Congo river, where an immense drop in elevation plunges the water of the Congo – the world’s second largest by volume, after the Amazon – with so much force that that the hydropower potential generated is enough meet the electricity needs of the whole of sub-Saharan Africa.

In 2013, South Africa ratified a treaty with the DR Congo that would see it financing part of the 40,000MW project to the tune of $17 billion; in return South African state-owned power company, Eskom, would receive 2,500MW of the 4,800MW produced by Inga III, the project’s first phase. 

Harnessing the immense hydropower of the Congo river would double Africa’s electricity generation capacity in a single stroke, but power shortages aren’t the only thing Congo could save.

From Oubangi to Lake Chad

One plan that is out of this world is to channel water from the Oubangi river – one of the Congo river’s main tributaries – to replenish the waters of Lake Chad, which have shrunk by more than 90% over the past 50 years.

At 25,000 sq.km in 1963, Lake Chad used to be Africa’s fourth largest lake. But higher evaporation rates in the arid Chad region – partly driven by climate change – and increased water withdrawals from feeder rivers for cotton and rice production have put increased demand on the lake, and it has dwindled to just 1,540 sq.km.

The idea to divert part of the Oubangi’s water into Lake Chad was first proposed in 1960s, but began to get international attention more recently. It involves creating a retention dam at Palambo, upstream from the city of Bangui, the capital of Central African Republic.

Water from the dam would flow by gravity through a navigable, 1,350 km man-made canal into the Chari-Logone river system, the main feeder of Lake Chad that supplies 95% of its water.

This arrangement would check the encroachment of the Sahara desert and act as a much-needed source of water for Sahelian communities – although Lake Chad is subject to much evapotranspiration, it is not saline, and so is one of the few sources of fresh water in the region.

Massive dam-canal system

It is also expected to generate power at the Palambo dam, as well as develop irrigation and agro-industry in the region.

But connecting the Oubangi with Lake Chad does something else, it gives a much needed infrastructure lifeline to the Central African Republic and northern DRC.

At the moment, transportation of goods from Bangui, in the heart of Africa, entails going by river barge on the Oubangi, and southward to the Congo River to enter the Atlantic Ocean.

But the water transfer from Oubangi to Lake Chad, and by extension, the Benue/Niger river system (via a canal to the Mayo Kebbi river, a tributary of the Benue) will facilitate the navigation and transportation of goods from Port Harcourt in Nigeria to central Africa, thus open up CAR and northern DRC for trade directly from Nigeria.

In 2012, Nigerian president Goodluck Jonanthan announced a feasibility study had shown the gigantic project was “feasible” and would “restore hope” to the populations living around the lake – about 30 million people depend on the Lake Chad basin for their livelihood.

But some have expressed concern that building such a massive dam-canal system would displace many communities in the area, and mixing of water from Oubangi to the Lake Chad basin could alter and destabilise the current ecology of the lake.

Crucially, it also could reduce the energy potential of the Grand Inga Dam.

Some have even questioned whether saving the lake is really worth it. The newly exposed lake bed has rich sediments deposited by the river flows into the lake, and so makes for very fertile soil - although fishing communities have been hit hard, farmers are having bountiful harvests.

Rwanda hack at the Kivu

Another big “nature hack” is proposed in Rwanda, where some 2 million people who live near Lake Kivu could face grave consequences if trapped volcanic gases rise to the surface.

Lake Kivu sits in a volcanic area between Rwanda and the DR Congo, where carbon dioxide and methane from below the earth surface seeps into the lake and lies quietly dissolved under 1,000 feet of water.

But an earthquake or a lava flow could loosen the trap and catastrophically release the gases, as happened in Cameroon in 1986, when a deadly cloud of carbon dioxide from Lake Nyos asphyxiated over 1,700 people. Under certain conditions, the newly released methane could even explode as it hits the air.

To avert danger, the Rwandan government has launched a grand engineering scheme to suck up explosive methane from depths of 1,000 feet and pipe it to a nearby power plant, generating 25MW of power.

The Rwandan government says the KivuWatt project could double the country’s electricity production and reduce its dependence on imported diesel fuel that currently powers a large share of its electricity.

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