The water level in man-made Lake Kariba, between Zambia and Zimbabwe, dropped to below 1% as the year ended, a situation that will bring drastic power cuts in both countries, very dependent on hydropower, informs The Washington Post.
The Kariba dam is the world's largest based on its reservoir capacity of 180,600 hm3, generating hydropower for millions in Zambia and Zimbabwe. The dam, finished in 1960, is on the Zambezi River, southern Africa’s longest transboundary river. The Zambezi River Basin is the fourth largest in Africa and spreads over eight countries.
Lack of rainfall upstream of Lake Kariba led to a record low level of 0.77% on December 31st 2022; in the past few days, the lake level has started increasing due to local rainfall on and around the lake, reaching 1.66% usable storage on January 9th 2023. On the same date last year, the usable storage was 20%, as per the data of the Zambezi River Authority.
Zambia and Zimbabwe both have their own power station on the north and south bank of the dam, with a generating capacity of 1050 megawatts and 1080 megawatts respectively, but both countries have seen their generating capacity reduced to less than 400 megawatts because of low lake levels.
Zesco, Zambia’s national power utility, announced on January 1st that the limitation would affect “the ability to meet the system load/customer power demand, especially during morning and evening peak demand periods.” It also said power outages would increase from six to 12 hours daily, although outages would be staggered into six-hour intervals to provide customers with some relief. Meanwhile, Zimbabwe is already facing 19 hours of outages every day.
Harry Verhoeven, a senior research scholar at the Center on Global Energy Policy in Columbia University’s School of International and Public Affairs, has highlighted the competent management reputation of the Zambezi River Authority (ZRA), in charge of transboundary waters and associated hydro-infrastructure, noting, however, that the crisis at Kariba has been in the making for years.
Climate change has led to increased temperatures and lower precipitation in southern Africa; on the other hand, the dam is badly in need of repair as the bedrock on which the dam was built has been eroded by routine operations, raising fears of a dam collapse. Both countries’ huge sovereign debt hinders their ability to pay for dam repairs and build the capacity to adapt to climate change.
“The revival of dams in Africa is stalling”, argues Verhoeven as he looks at the implications of the situation at Kariba dam for hydropower in the African continent. He points to obstacles that include displacement politics and the long time-horizons for dam planning and investment, which require extensive external support for most African states. Moreover, as reservoir water levels drop at Kariba and globally, it is becoming clearer that dams might not live up to their promises of providing electricity and irrigation in the face of climate change.
