Even if you usually find engineering talk as enticing as imagining your parents having sex (eeuw!), it’s hard to resist the fascination of Lesotho’s Katse dam project once you stand next to the dam wall and discover just how bug-like you are by comparison. It’s even harder not to be impressed when you consider some of these facts that everyone should know.
1. The wall is 185 metres high, 60 metres wide at the base, 9 metres wide at top and curves from side to side as well as from top to bottom, making it one of only 30 double-curved concrete arch dam walls in the world.
2. During the initial excavation, it was discovered that the bedrock was seismically unstable so the clever engineers incorporated a moveable joint in the dam’s base to allow it to flex. How smart is that?
3. It took six years and 2.32 million cubic metres of concrete to build. In fact, a truckload of cement and fly ash, transported by road from Ficksburg, was delivered every 40 minutes during the construction phase.
4. Katse is the second-highest dam in Africa after the Tekeze dam in Ethiopia (185m compared to Tezeke’s 188m). Katse is also one of the world’s ten largest concrete arch dams in terms of volume, with a capacity of nearly 2 billion cubic metres and a surface area of 38.5 square kilometres.
2. During the initial excavation, it was discovered that the bedrock was seismically unstable so the clever engineers incorporated a moveable joint in the dam’s base to allow it to flex. How smart is that?
3. It took six years and 2.32 million cubic metres of concrete to build. In fact, a truckload of cement and fly ash, transported by road from Ficksburg, was delivered every 40 minutes during the construction phase.
4. Katse is the second-highest dam in Africa after the Tekeze dam in Ethiopia (185m compared to Tezeke’s 188m). Katse is also one of the world’s ten largest concrete arch dams in terms of volume, with a capacity of nearly 2 billion cubic metres and a surface area of 38.5 square kilometres.
Katse dam's wall is 185 metres high
5. There’s a series of parallel galleries inside the dam wall that use precision laser instruments to check on the wall’s movement and the dam’s behaviour. The galleries also act as drainage tunnels for water seepage from the mountain. If you go on a tour you’ll discover that it’s cold and damp inside the wall, with white stalactites in the sections that tunnel into the mountain.
6. Katse dam is the transfer reservoir for the whole Lesotho Highlands Water Project. All the water captured by the different structures (like Mohale Dam, which is connected to Katse by a 32km-long tunnel) flow from it to South Africa via Clarens in the Free State.
7. The Katse dam provides 72 megawatts of electricity for Lesotho.
8. Lesotho earns some R25 million in export revenue every month for supplying South Africa with water.
6. Katse dam is the transfer reservoir for the whole Lesotho Highlands Water Project. All the water captured by the different structures (like Mohale Dam, which is connected to Katse by a 32km-long tunnel) flow from it to South Africa via Clarens in the Free State.
7. The Katse dam provides 72 megawatts of electricity for Lesotho.
8. Lesotho earns some R25 million in export revenue every month for supplying South Africa with water.
View from the top of the wall
9. As a result of the project, Lesotho got 100 kilometres of new tar road and 260 kilometres of new gravel road, while 1000 kilometres of existing gravel road was upgraded. The project also created jobs, especially near Butha-Buthe and the Ash River Outfall near Clarens in the Free State, which is the final stage of the tunnels that take water to Gauteng.
10. The flip-side is that once-remote mountain villages were changed dramatically. Some 20 000 people lost their homes, farmland or communal grazing grounds (although similar-sized new homes were provided elsewhere). But the effects are still being felt today, with some communities that used to share social ties now cut off from each other by the reservoir.
11. Phase 2 was set to begin near Mokhotlong in 2014 and expected to take five to six years before it finally joined with Katse dam via a tunnel.
12. Fish in the dam include trout and indigenous yellow fish. There are some nursery projects for the fish (you can see one not far from the Katse Lodge). Trout are farmed for local consumption and export.
Need to know
Tours start from the visitor centre; with its bright blue roof, you can’t miss it. Tours cost R30 per person (in November 2018) and take about an hour, starting at 9:00 and 14:00 during the week, and 9:00, 11:00 and 14:00 on Saturdays, Sundays and public holidays.
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10. The flip-side is that once-remote mountain villages were changed dramatically. Some 20 000 people lost their homes, farmland or communal grazing grounds (although similar-sized new homes were provided elsewhere). But the effects are still being felt today, with some communities that used to share social ties now cut off from each other by the reservoir.
11. Phase 2 was set to begin near Mokhotlong in 2014 and expected to take five to six years before it finally joined with Katse dam via a tunnel.
12. Fish in the dam include trout and indigenous yellow fish. There are some nursery projects for the fish (you can see one not far from the Katse Lodge). Trout are farmed for local consumption and export.
Need to know
Tours start from the visitor centre; with its bright blue roof, you can’t miss it. Tours cost R30 per person (in November 2018) and take about an hour, starting at 9:00 and 14:00 during the week, and 9:00, 11:00 and 14:00 on Saturdays, Sundays and public holidays.
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Copyright © Roxanne Reid - No words or photographs on this site may be used without permission from roxannereid.co.za
18 things to do in Lesotho, Southern Africa
The truth about Katse Lodge in Lesotho
More about Lesotho
Copyright © Roxanne Reid - No words or photographs on this site may be used without permission from roxannereid.co.za
