By Julienne du Toit. Photographs by Chris Marais
Up until 1976, the Great Fish River was very different to the cappuccino-brown fast flow that it is today.
Farmers living alongside its banks and Cradock residents had to cope with an unpredictable and seasonal waterflow. During rains it flowed clear and broad. In winter it dried up to a series of green puddles. The Eastern Cape Midlands had so much promise because of its rich arable soil, yet its potential remained locked away for lack of water.
But the building of the Gariep Dam changed all that. Once it was finished in 1971, the dam waters were available for irrigation. But first it was necessary to link the Great Fish River to the dam and to do that, a very long enclosed aqueduct had to be dug through the Suurberg Mountains.
This was a project that needed highly specialised engineering, so the South African government of the time sought out experienced and junior engineers from England, Portugal, West Germany, France, Belgium, Italy and Spain to help with the design and construction.
A French, an Italian and a South African team all worked simultaneously on lengths of the tunnel. Even the curvature of the earth was taken into account when setting out the levels.
The miners dug through mudstone, ironstone, sandstone, and lethally explosive pockets of methane.
Most people have forgotten the staggering human loss. No fewer than 102 people died building this tunnel, many of them from foreign lands.
When the tunnelling teams met one another in 1975, they were less than 4mm out of alignment.
At just under 83km, the Orange-Fish Tunnel is the world’s third-longest aqueduct, ending at the distinctive hill called Teebus between Middelburg and Steynsburg.
Here, a quarter of the Gariep Dam’s waters pour into the Teebus Spruit, which flows into the Brak River, and then into the Great Fish. Further south, the there is a link into the Sundays River via a canal near Somerset East.
- For 5 or 6 weeks during June and July, the tunnel is emptied for inspection and maintenance. During this time members of the public are welcome to have a look at the tunnel, and even drive through a circular part of it. Because methane levels can rise, only diesel vehicles are allowed. The tunnel is also never completely dry, and anyone wanting to explore it should bear in mind there will be darkness, confined spaces, splashing fish and the odd crab. Bring gumboots.
To organise a visit, call Lettie Dipenaar on 051 754 0001/2.