The Zambezi and the Kariba Dam
In the far northwest of Zambia, close to that country’s borders with Congo and Angola there is an apparently unremarkable sandstone ridge, Kalene Hill. Unremarkable, that is, until it is realised that it marks the source of one of Africa’s longest rivers, the Zambezi. From this point, the river flows for almost 2,600 km (1,600 miles) through Zambia, Angola, Namibia, Botswana, Zambia (again), Zimbabwe and Mozambique to its delta on the Indian Ocean. En route, it creates one of the world’s greatest natural wonders, known locally as ‘Mosi-oa-Tunya’ (translated as ‘The Smoke that Thunders’, describing the effect, from a distance, of the spray rising above it). These are the Victoria Falls, so named – in honour of his Queen - by the first European recorded to have viewed them, the missionary and explorer David Livingstone.
The river and the engineering structures with which it is associated were the subject of a recent talk to the Bakewell and District Probus Club by one of its members, Alan Grant. One of the most famous of these structures described by Alan was the Victoria Falls Bridge, a steel arch across the gorge of the Zambesi immediately below the Falls where, according to the wishes of its instigator, Cecil Rhodes, “the trains, as they pass, will catch the spray of the Falls”. The original bridge was completed in 1905 but has subsequently been strengthened and adapted to include a road as well as the railway line. It is an important and busy crossing point between Zambia and Zimbabwe.
A much more recently built bridge is a combined road and rail structure, linking Zambia and Botswana at the site of a former ferry at Kazungula. This bridge, inaugurated in 2021, is notable for being curved in plan. It was designed on this alignment to avoid the nearby borders of Namibia and Zimbabwe.
Having discussed these two civil engineering features of the Zambesi, the speaker turned to another major structure, the Kariba Dam. Started in 1955 and completed four years later, this dam is 579m (1,900 ft) long, 128m (420 ft) high and has created the huge Lake Kariba upstream. Extending for 280km (170 miles) this is one of the world’s largest man-made lakes and provides the water needed for the two hydro-electric power stations incorporated in the dam. Unfortunately, the whole scheme is now suffering from a number of problems including the effects of drought on the availability of water to power the turbines in the power stations, aging machinery and equipment, and the danger of the dam itself becoming unstable through erosion of its foundations. Clearly, if the dam were to fail, the consequences downstream would be catastrophic but, thanks to the efforts of the international community, a project to strengthen these foundations, the Kariba Dam Rehabilitation Project (KDRP), is now under way and is scheduled to finish in 2025, no doubt to the relief of all concerned.
Details of the Bakewell and District Probus Club, including reports of earlier meetings, can be found on its website at www.bakewell probus.org