‘Levels are dropping’: drought saps Zambia and Zimbabwe of hydropower

Vast human-made Lake Kariba is at near-record low, causing daily power cuts and devastating two African economies

All is not well with the waters of Lake Kariba, the world’s largest human-made lake. A punishing drought has drained the huge reservoir close to record lows, raising the prospect that the Kariba Dam, which powers the economies of Zambia and Zimbabwe, may have to shut down for the first time in its 65-year history.

Under the heat of the dry-season sun, the lake looks vast, serene. But, earlier this year, a severe effect of El Niño caused the worst mid-rainy season dry spell in southern Africa in a century.

That has led to authorities rationing the water allowed to flow through the dam and, in recent months, power cuts of up to 21 hours a day in Zambia on the lake’s northern side and 17 hours in Zimbabwe to the south.

The load shedding is devastating livelihoods and hitting the countries’ already weak economies – Zambia is still recovering from a drawn-out debt restructuring and Zimbabwe is throttled by chronically high inflation. Average temperatures have already been rising in recent decades in both countries as climate breakdown takes hold.

“This is the worst [it’s ever been],” said Cephas Museba, the manager of the hydropower plant on Zambia’s side of the lake, who has worked for the country’s national power company, Zesco, since 2005.

He pointed out concrete beams that were usually under the reservoir’s surface. On the other side of the dam, below its 128-metre high concrete wall, were dark brown rocks rising in an island from the Zambezi River, which forms the border between Zambia and Zimbabwe. “Everything brown there, down there, is supposed to be under water,” Museba said. “All the year.”

The Kariba Dam was built between 1955 and 1959, when Zimbabwe and Zambia were still under British colonial rule. Queen Elizabeth the Queen Mother presided over its official opening in 1960, after an estimated 80 to 100 workers were killed during its construction.

The flooding of the land behind the dam, creating the roughly 150 mile-long lake, displaced about 57,000 people. About 6,000 large animals were rescued from the rising waters, an effort known as Operation Noah.

Now, the Zambezi River Authority splits the allocation of the water flowing into the 180bn cubic metre reservoir between Zambia and Zimbabwe. Zimbabwe’s 1,050MW power station accounts for about 38% of the country’s generating capacity. Zambia’s 1,080MW counterpart represents about a third.

In Zambia’s underground power station, Museba pointed out six big metal cylinders hosting the power station’s turbines. But only one turbine was being run at partial capacity to conserve water.

“My preference is to run two units, because if you’re running one and it trips because of a fault, then you risk going into a blackout,” Museba said, his steady manner not quite masking the concern. “The other years when we were hit with drought, we were remaining with at least two machines.”

The drought has also wiped out crops, with hunger stalking much of southern Africa. Lesotho, Malawi, Namibia, Zambia, and Zimbabwe have declared a national disaster and parts of Angola and Mozambique are also affected.

In Zimbabwe, small businesses are struggling to survive without a regular power supply.

“Sometimes I fail to meet orders because of the lack of electricity,” said Handsome Maurukira, who owns a small metalworking business on the outskirts of Harare. He said he was spending about $400 a month on diesel and only just staying afloat.

On Lake Kariba’s Zimbabwe shoreline, fishers said they were lucky to catch even one 25kg crate of kapenta, a slim silver fish smaller than a finger. Before, they would pull in a tonne every night.

“The situation is getting worse. The water levels are dropping. Sometimes you see an island where you normally should not see an island,” said Peter Mashonga, a 64-year-old boat captain. “This is not the first time for the lake to drop. But, the way it has dropped now, it is worse than in 1996, when it last happened.”

“We ask God to give us rain this year because things are not looking well for the future of fishing,” said Pride Dzomba, a fisher.

Zimbabwe’s economic growth is expected to slump this year to 2% from 5.3% in 2023. In October, the International Monetary Fund cut its 2024 forecast for Zambia’s growth from 2.3% to 1.2%.

Blame has been flying around Zambia, with disgruntled citizens and opposition politicians claiming that Zesco, which started power cuts in March, could have done more to conserve power earlier in the year. The rainy season was even worse than the company forecast, said Wesley Lwiindi, Zesco’s director of power generation.

There was an agreement, though, that more diverse power sources were needed – and that this was a lesson that should have been learned from droughts in 2015 and 2019. New coal and solar plants are now being built in Zambia and Zimbabwe. Zambia’s government also wants to add hydroelectric dams to rivers in its wetter north-west.

Jito Kayumba, a special adviser to Zambia’s president, said: “This is not particularly good news for promoters of sustainability and matters of climate, but we are doubling down on coal … because we do have an abundance of coal.

“[Coal] will still represent a minor piece of our energy mix. We still want to enhance more renewable sources of electricity. But we also realise that we do need energy security.”

Back at Kariba Dam, on 18 October Museba said the reservoir’s depth – then 77cm away from requiring the power station to be closed down completely – was falling at a rate of 1cm a day.

The Zambezi River’s catchment area usually starts to get rain around October and November, taking two to three months to reach the dam downriver. This year, thankfully, Zambia’s November-to-April rainy season is forecast to be normal, Museba said.

But, with the lake often not starting to rise until early January, rain can’t come soon enough: “If we can have the early rains that would be much better,” he said. “You can see that we are not doing fine.”

Cover photo: Exposed islands of rocks can be seen in the depleted Zambezi River, which feeds the Kariba Dam. Photograph: Rachel Savage/The Guardian