New measurements show just how much pristine water Verloren Valei contributes to the total ecosystem.
By James van den Heever
The last time a scientific study of the water provided by the Verloren Valei wetlands was in October 1995. Now, sterling work by Jannie Coetzee, Elizma Coetzee and Hannes Marais provides figures for March 2021. The results demonstrate clearly the huge volumes of pristine water that the reserve contributes to the country’s water system.
The October 1995 readings took place at a time of low flow after the dry winter, and in this case after a period of lower than average rainfall. By contrast, the March 2021 readings were taken at a high-flow time after an exceptionally wet summer.
In each case, the surveys included all the streams originating in the reserve, with measurements taken as close to the fence line as possible. The 1995 survey covered 12 streams, whereas the 202i only covered 11 as one stream had become a wetland with no channel to measure water flow.
So how do the two sets of figures compare. The October 1995 figures, which the authors believe could represent the bare minimum of water supplied by Verloren Valei amounts to 14 million litres per 24 hours. The high-flow figures from March this year are 600 million litres per 24 hours, with the largest contributor being the Klipbankspruit which feeds the Olifants River system via the Steelpoort River. The reserve sits on a watershed, with its south- and east-flowing streams flowing into the Crocodile River system—indeed, the Crocodile itself rises in the south-east corner of Verloren Valei.
The authors make the important point that an accurate estimated value of annual water production will only be possible after several years of high- and low-water flow measurements have been made.
In the meantime, it’s good to have some figures to express just what sort of value this reserve, and others like it, create for the country.