Posts Tagged ‘zimbabwe’
[URBAN NOTE] Five Toronto links: extreme weather, Jodi Emery, Little Jamaica, public art, Mnandi pie
- Matt Elliott at CBC Toronto asks what, exactly, the City of Toronto is doing to prepare for the increasingly erratic and dangerous weather hitting the city.
- NOW Toronto reports on how Jodie Emery plans to start expanding her marijuana empire, and her wider influence, after opening a new café in Kensington Market.
- This NOW Toronto article reporting on some of the restaurants of Little Jamaica, along Eglinton Avenue West, is informative.
- I honestly have to say that I have taken note of Three Points Make Two Lines, down at Vaughan Road and St. Clair Avenue West. I will. Murray Whyte at the Toronto Star makes the case.
- Suresh Doss describes the Mnandi pies sold by Evis Chirowamhangu at Wychwood Barns.
[LINK] “One of Africa’s Biggest Dams Is Falling Apart”
In The New Yorker, Jacques Leslie examines how the Kariba Dam on the Zambia-Zimbabwe border is one predictable disaster away from collapse.
The new year has not been kind to the hydroelectric-dam industry. On January 11th, the New York Times reported that Mosul Dam, the largest such structure in Iraq, urgently requires maintenance to prevent its collapse, a disaster that could drown as many as five hundred thousand people downstream and leave a million homeless. Four days earlier, the energy minister of Zambia declared that Kariba Dam, which straddles the border between his country and Zimbabwe, holding back the world’s largest reservoir, was in “dire” condition. An unprecedented drought threatens to shut down the dam’s power production, which supplies nearly half the nation’s electricity.
The news comes as more and more of the biggest hydroelectric-dam projects around the world are being cancelled or postponed. In 2014, researchers at Oxford University reviewed the financial performance of two hundred and forty-five dams and concluded that the “construction costs of large dams are too high to yield a positive return.” Other forms of energy generation—wind, solar, and miniature hydropower units that can be installed inside irrigation canals—are becoming competitive, and they cause far less social and environmental damage. And dams are particularly ill-suited to climate change, which simultaneously requires that they be larger (to accommodate the anticipated floods) and smaller (to be cost-effective during the anticipated droughts).
[ . . . Kariba] has been nearly incapacitated by ongoing drought, which has lowered the reservoir’s volume to twelve per cent of its usual capacity. But if the reservoir is refilled, the dam faces the possibility of collapse. It was built in the late nineteen-fifties, and in the years since water flowing through the dam’s six floodgates has carved a three-hundred-foot-deep pit, or plunge pool, at its base. The plunge pool extends to within a hundred and thirty feet of the dam’s foundation; if it reaches the foundation, the dam will collapse. That seems hard to imagine now, with the reservoir at a record-low level. But the Zambezi River Basin, on which the dam sits, is the most susceptible of Africa’s thirteen basins to exceptional droughts and floods, and climate change is intensifying both.
Kariba’s collapse, like Mosul’s, would constitute an epochal event in the history of energy development—the dam industry’s Chernobyl. The ensuing torrent would be four times bigger than the Zambezi’s biggest recorded flood, in 1958, and would release enough water to knock over another major dam three hundred miles downstream, in Mozambique. At least three million people live in the flood’s path; most would die or lose their crops or possessions. About forty per cent of the electricity-generating capacity of twelve southern African nations would be eliminated.
The dam, four hundred and twenty feet tall and nearly two thousand feet wide, was built with financing from the World Bank to provide power for the copper mines of what was then Northern Rhodesia. The designers intended to make the dam impervious to a one-in-ten-thousand-year flood, but their calculations were based on only three decades of Zambezi flow data—a period too short to permit credible forecasting. This flaw became apparent in 1957, when the site, still under construction, was hit with a flood bigger than the designers’ worst-case projection. The planners hurriedly enlarged the spillway, but in 1958 the project was hit by another flood, twice as big as the previous one, so the spillway was expanded again. More recent projections, cited by the Intergovernmental Panel on Climate Change, indicate that the Zambezi River Basin will experience still drier and more prolonged droughts and even bigger floods in years to come.