The Other Site Was Kafue
In 1955 the Federation of Rhodesia and Nyasaland chose to dam the Zambezi at Kariba rather than the Kafue, a river that runs entirely inside Northern Rhodesia, and the first machine hall went on the southern bank. Zambia has spent the seventy years since building its way out of that decision, and a drought in 2024 showed how much of the job was left.
The road along the top of the Kariba dam is an international border. You show a passport at one end and a passport at the other, and between them you are standing on a double-curvature concrete arch 128 metres high, closed in 1959, holding back the largest reservoir by volume that anyone has ever built. Look downstream on the Zimbabwean side and there is a machine hall that has been generating since 1960. Look at the Zambian side and there is a second machine hall, cut into the rock, which did not produce a unit of electricity until 1976.
Sixteen years is a long gap for two halves of the same dam, and it is not an accident of construction sequencing. It is the residue of a choice made in 1955, when the Federation of Rhodesia and Nyasaland — two years old, and financed to a very large extent by the copper mines of the Northern Rhodesian Copperbelt — had to decide which river to dam. There were two schemes. One was the Kafue Gorge, on a river that rises and ends inside Northern Rhodesia, closer to the mines that needed the power, cheaper, and buildable in stages as demand grew. The other was Kariba, on the Zambezi, which is the border.
Two sites, one assembly
The Federal government settled on Kariba, and the engineering case for it was real: far greater storage, a single large scheme rather than a sequence of small ones, and enough water banked to hold output steady through a dry year. Northern Rhodesian opinion read it politically anyway, and the reading was not paranoid. The Federation was governed from Salisbury. An asset on the border, with its generators on the southern bank, would still be a southern asset if the Federation came apart — which it did, on the last day of 1963. Construction went to an Italian consortium and ran from 1955 to 1959; the Zambezi came down in flood twice during the works and wrecked them both times, and the commonly cited toll is eighty-six men dead.
The valley they emptied
Filling the lake took until the early 1960s and covered something over five thousand square kilometres of the Gwembe valley, which was not empty. Around 57,000 Gwembe Tonga were moved between 1957 and 1958, the larger share of them on the northern bank, off alluvial riverside gardens and onto thinner soils away from the water. The compensation and the services that were promised largely did not follow. In September 1958, at Chisamba Lwanga in the valley, tear gas failed to shift Tonga who refused to go, police fired, and eight people were killed and thirty-two wounded. Two anthropologists, Elizabeth Colson and Thayer Scudder, started recording what happened to those villages in 1956 and kept going for more than fifty years, which is why the Gwembe resettlement is one of the best-documented displacements in the world — and why nobody can claim the outcome was not known.
The Federation lasted ten years. The lake it argued about is still there, still shared, still generating, and the villages that went under it are still under it.
Sixteen years for the second machine hall
A north bank station was in the design from the start and simply was not built. Northern Rhodesia became Zambia in October 1964 and inherited a dam on its own border whose every turbine sat in another country — a country whose white minority government declared unilateral independence in November 1965, and against which Zambia then spent years enforcing sanctions. The north bank station was finally commissioned in 1976, at 600 MW; its four machines were later uprated to 720 MW between them and an extension added another 360 in 2013, which is how it reaches the 1,080 MW it has now. In the meantime Zambia went and built the scheme it had wanted in 1955: the Kafue Gorge power station, first units running from 1972, eventually 990 MW, and the largest in the country for the four decades until the Kariba extension overtook it. In 1987 the two states replaced the old Central African Power Corporation with the Zambezi River Authority, owned equally by both, which holds the dam itself and divides the water between the two national utilities in identical shares.
The hole under the wall
Kariba spills through six sluice gates into a plunge pool, and decades of flood releases scoured the basalt into a crater roughly eighty metres deep that was working its way back towards the foot of the arch. The Zambezi River Authority assembled a rehabilitation project costed at around 300 million US dollars — World Bank, European Union, African Development Bank and Sweden — and work began in 2017. Two jobs: reshape the plunge pool so the water lands where it is supposed to, and refurbish the six gates, which in drought years are opened so rarely that seizure becomes the risk rather than erosion. The reshaping is substantially done. Neither government could have financed it alone, and neither could afford to leave it, because what is below the wall is a populated valley and two national parks.
Twenty-one hours
Zambia takes the great majority of its electricity from water, and Kariba North Bank alone is close to a third of installed capacity. In the drought of 2015 and 2016 the lake's usable storage fell to roughly a tenth and the utility put the country on eight hours of load-shedding a day. The El Niño drought of 2023 and 2024 was worse. The president declared it a national disaster in February 2024, the maize crop failed across the southern half of the country, and by December usable storage at Kariba was effectively gone — under one per cent — with only a fraction of the machines able to turn. Load-shedding reached twenty-one hours a day. That is what a grid built on one reservoir does when the reservoir is empty, and it is the bill for a siting decision taken by an assembly that has not existed since 1963.
The response is the part that gets reported less. Zambia was the first country anywhere to complete an IFC Scaling Solar auction, in 2016, at a winning tariff of about six US cents a kilowatt-hour — then the lowest in sub-Saharan Africa — and the two plants it produced, Bangweulu at 54 MW and Ngonye at 34 MW, have been running south of Lusaka since 2019. Kafue Gorge Lower, 750 MW, came on in the early 2020s. Duty and VAT were stripped off imported solar equipment, and private companies were licensed to buy power across the border directly instead of queuing behind the utility. None of it is finished and none of it yet substitutes for a reservoir. But it is worth knowing, standing on that wall with a passport in your pocket, that the country on the northern bank started building its way off this lake four years before it was allowed a machine hall of its own — and that the argument which started all of it was about a gorge on the Kafue.