Thursday, 1 October 2015
Taming the Groot Vis
But - beyond the world of fiction - could the Groot Vis (pictured here in calm mood) be tamed to produce a steady flow of water on its way to the sea? Could it turn arid acres into productive farmland, while at the same time avoiding the catastrophic cycle of drought and flood?
Engineers in the 1960s and 70s believed it could. They conceived an ambitious scheme to divert water from the Orange River to the north, into the Great Fish via a series of tunnels, dams and weirs that would both increase and control the flow of water. No more floods. No more drought. Instead, a steady supply of water. In its day, this project was a huge undertaking. Apart from the dams, an 82 km tunnel had to be built to channel the water from the Gariep Dam to the Fish River valley. When completed in 1975, the tunnel was the longest closed aqueduct in the southern hemisphere and the second longest water supply tunnel in the world.
Has it worked?
Ah, now that has divided opinion!
Certainly, the potential for flooding in Cradock and towns further downstream has been reduced. And, with a controlled flow, the droughts are no longer as devastating. But... such a vast project was always likely to have some uncertain results. The dream of creating extensive irrigated croplands has not been totally fulfilled. It turns out that in some areas, ancient salty deposits have been liberated by the water and risen to the surface to render the soil less fertile. And environmentalists worry that the blending of waters from two separate watersheds has seen the proliferation of Orange River flora and fauna within the Fish River system...
The battle for water - and the taming of rivers by damming and diversion - is a global dilemma. On the Colorado in the US, the Yangtze in China, on the Mekong in Vietnam and Cambodia... Where does the balance lie?
For Ada and Mrs Cath, the wild Groot Vis is both a vital resource and a portent of future events.
I was lucky with the river that day. The drift was open. I sat down on the riverbank to take off my shoes. It would not do to get them wet - they were the only shoes I had. The brown water of the Groot Vis slipped smoothly over my feet as I waded across.
At first it was a brisk eddy, then a howl of demented water. The drift disappeared beneath angry waves, the legs of the bridge were choked with uprooted trees.
"Oh God," Mrs Cath cried, pressing her hand to her chest, "this is the whirlwind, I know it is -"