Praying for rain Drought drains African countries' vital hydropower

All is not well with 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.

- Rachel Savage & Nyasha Chingono

Under the dry-season sun, the lake looks vast, serene. But, 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 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 already weakened economies - Zambia's is still recovering from a drawn-out debt restructuring while Zimbabwe's is throttled by chronically high inflation. Average temperatures have risen in recent decades in both countries as climate breakdown takes hold.

"This is the worst it has been," said Cephas Museba, 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 surface. On the other side of the dam, below its 128-metre high concrete wall, were dark brown rocks rising from the Zambezi River, which forms the border between Zambia and Zimbabwe. "Everything brown down there is supposed to be under water," Museba said. "All the year."