World's Biggest Dam Has ‘Extremely Dangerous’ Low Water Levels
Water levels at Kariba dam, the world’s largest, are at “extremely dangerous” lows that could force a shutdown of its hydro power plants, said Zambian Energy Minister Dora Siliya.
Poor rainfall and overuse of water by Zambia and Zimbabwe, the southern African countries that share the reservoir, have caused its levels to drop, with electricity generation already reduced by more than half. As of Dec. 28, Kariba was 14 percent full, compared with 51 percent a year earlier, according to the dam’s regulator.
“The situation is dire,” Siliya told reporters Thursday in Lusaka, Zambia’s capital. “I’m praying. We sit here and gaze at the sky and say, ‘please, the levels of Kariba are at extremely dangerous levels.’” A continued absence of rains could force the power plants to shut down altogether, she said.
Mining companies in Africa’s second-biggest copper producer have had to reduce their electricity use and buy expensive imports at a time when plunging metal prices have triggered the mothballing of some mines and more than 10,000 job cuts. Households and businesses endure power cuts as long as 14 hours a day. The cost of importing power and emergency generation could threaten the government’s 3.8 percent budget deficit target for 2016.
Zambia is the most vulnerable country in sub-Saharan Africa to the El Nino weather system, partly because of its dependence on hydro power for more than 95 percent of generation, Bank of America Merrill Lynch analysts including Oyinkansola Anubi said in a November note. Six of Zambia’s 10 provinces have received below-normal rainfall this wet season, Meteorological Department director Jacob Nkomoki said in comments broadcast on Lusaka-based Radio Phoenix Dec. 4.
Water flows in the Zambezi river that feeds Kariba on Dec. 28 were 27 percent lower than a year earlier when measured at the Victoria Falls, about 125 kilometers (78 miles) upstream from the dam, according to data from the Zambezi River Authority. At Chavuma, about 600 kilometers north-west and near the river’s source, flows had started to improve and were 23 percent higher on Dec. 28 than a year earlier.
Water levels at Kariba on the same date were 477.57 meters (1,567 feet) above sea level, barely exceeding the minimum of 475.50 meters for hydro power operations, according to the authority. The government will spend $1.2 billion to mitigate the power crisis, Siliya said.
The Zambian government has prepared for the possibility of halting generation at Kariba, Siliya said. The measures include setting up emergency thermal power plants due to produce 250 megawatts by early March, as well as a 200-megawatt power-ship to be docked off the coast of neighboring Mozambique, she said. A 300-megawatt coal power station is also expected to start operations by June.
The country’s power deficit would grow to 1,000 megawatts by the end of December 2015, about half of normal peak demand, Siliya told lawmakers in November. Kariba may have to shut down by October this year if rainfall is low and Zambia and Zimbabwe continue to overuse its water, she said at the time.
“Our contingency is to make sure that even if we have to shut down there must be power coming,” Siliya said Thursday. “God forbid where we should have a situation where we might say we have to shut them down because the water level is below the minimum recommended.”