Tufa Waterfall EarthCache
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Tufa Waterfalls are rare in South Africa, and as far as we know,
this is the only one which can be viewed from a public road. On the
R36 north of Ohrigstad/Blyde Canyon (Abel Erasmus Pass), park at
the viewpoint at the southern end of the J G Strydom Tunnel.
This Tufa Waterfall can be seen across the gorge almost due south
of the viewpoint. Please do not attempt to approach the waterfall -
the terrain is dangerous, and probably impassable unless you are an
experienced rock climber.
Tufa Waterfalls are unique. Most waterfalls cause the erosion of
rocks, while a Tufa waterfall creates rock through sedimentary
deposits of limestone over millions of years.
A Tufa Waterfall is created when water running over dolomite rock
absorbs calcium, and becomes supersaturated with calcite.
Supersaturation typically occurs at a waterfall, when the water is
highly aerated, has an accelerated flow velocity, and an
enlargement of the air/water interface area. This accelerates the
release of carbon dioxide, which promotes calcite precipitation. It
is believed that algae and mosses, which grow abundantly on the
porous tufa deposits, assist with the removal of carbon dioxide,
and also create the necessary substrate to trap the calcite
precipitation.
The photo below was taken shortly after heavy rains. You will see
that the river flows beneath the hard crust of the large dome
shaped Tufa deposit which fills the valley, and emerges from a
small cave-like hole. There are also several other holes where the
river has previously flowed. All the tufa making up the massive
dome was deposited over the millenia by the river.
There is another nearby Tufa Waterfall, Kadishi Falls at the inflow
of the Blydepoort Dam, which can be viewed either from the guided
Kadishi-Tufa hiking trail which starts from Aventura Blydepoort
(top), or from guided boat trips on the Blydepoort Dam near
Aventura Swadini (bottom).
For the bird watchers - the rare and endangered Taita Falcon can be
seen nearby. Please refer to the log entry by g.i.s. dated 30th
January 2008 for more info.
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To log this cache, you need to:
- Estimate the approximate width and height of the Tufa dome.
- Name the primary difference between tufa waterfalls and normal
waterfalls.
- And send us your answers by email. Please do not quote your
answers in your log.
Please upload a photo of yourself with the Tufa dome in the
background, taken from the viewpoint.
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