Harvesting water from fog in Limpopo

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image: watersense.co.za
South Africa is following the lead of a desert beetle in tackling the problem of water scarcity in the country’s drought-prone Limpopo province, where remote rural communities live far from reliable water sources – yet in areas that are often shrouded in mist.
For years now, members of Vondo Village, in the Thulamela Municipality in Limpopo, have been implementing an innovative solution to their water shortage problem, using special nets erected at Tshanowa Primary School to harvest drinking water from fog.
With the nearest water sources being a non-perennial spring about two kilometres away, and a dam about five kilometres away – and with water source contamination rife in the province – the fognets have given the school children and the wider community a lifeline.
It’s a method followed by the Namib fog beetle, which has net-like hairs on its underside that enables it to harvest water from the sea-fog that rolls in over the desert every morning.
The Tshanowa Primary School research project was led by University of South Africa (Unisa) climatologist Jana Olivier, an associate professor at Unisa’s School of Agriculture and Environmental Sciences. Olivier has since been involved in setting up similar research projects in half a dozen places across South Africa.
Now, Unisa and University of Pretoria have partnered with the South African Weather Service and the Department of Water Affairs to give the Tshanowa Primary School project additional backing, while formalising it and extending it to Tshiavha Primary School in Tshiavha village, also in the Thulamela Municipality.
“These fognets have over the years been providing water to local communities,” Deputy Water and Environmental Affairs Minister Rejoice Mabudafhasi said at the launch of the Fognet Project at the Mphephu Holiday Resort in Limpopo this week.
Mabudafhasi added that the Fognet Project had the additional virtue of bridging the gap between science and day-to-day living.
Members of the two universities and the South African Weather Service are training members of the two communities to maintain the fognets.

According to the Science in Africa website, which ran an article on the Tshanowa Primary School project some years ago, “each fog collector consists of three 6m-high wooden poles, mounted 9m apart. Steel cables stretch horizontally between the poles, and from each pole to the ground. A double layer of 30 percent shade cloth is draped over the cables, and fixed to the poles on each side.
“Water dripping from the net into the gutter runs through a sand filter and is then emptied into a tipping bucket,” Science in Africa reporterd. “From there, it flows into a 10kl storage tank further down the slope. Two additional tanks were erected at the school to collect the overflow from the first. An automatic weather station was also installed to record rainfall, wind speed and wind direction.
“Within four days of completion, school children and members of the local community were drinking water collected by the fog screen … the giant fog screens at Tshanowa Junior Primary School … are providing pupils and members of the community an average of between 150 litres and 250 litres of water per day.”
southafrica.info

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