A climatologist from the University of South Africa (Unisa) has helped develop a low cost, eco-friendly system to harvest moisture from abundant mountain fog in a water-scarce region of the Eastern Cape, and communities there are already benefiting from it.

The project was successfully launched in Cabazane Village, in the rural Mount Ayliff area in the north of the province, in mid-March 2010 during the annual National Water Week.

The area, which falls in the picturesque Alfred Nzo district municipality, is bordered to the north by the mountain kingdom of Lesotho and much of the terrain is steep and remote, with very cold winters and mild summers. Fog is a frequent visitor and a ready source of clean water.

Professor Jana Olivier of Unisa’s School of Agriculture and Environmental Sciences has spent the past 20 years specialising in the properties and hazards associated with fog, especially for vehicles.

She later started delving into the technique of fog harvesting. “We got funding from the Water Research Commission, and we designed the fog water system,” she said.

Olivier teamed up with Professors Johan van Heerden, Hannes Rautenbach and Tinus Truter – all of Pretoria University – in the development of the system.

Unisa is involved in ongoing research into water harvesting from fog, especially for isolated rural communities, where water is scarce and villagers often have to walk vast distances to fetch a few litres at a time.

However, the system is only practical where fog occurs for at least 40 days a year, and for a period of several hours at a time.

The project has also been rolled out in other dry areas of South Africa, including Venda, Limpopo, and the West Coast, but Mount Ayliff’s persistent fog yields the best results, producing hundreds of litres of water a day.

“The West Coast and the mountainous areas – stretching from the Soutpansberg in the north, along the Drakensberg in the east to the Cape Mountains in the south – have the highest fog harvesting potential,” said Olivier.

Mount Ayliff is located in the Umzimvubu local municipality, one of two municipalities within Alfred Nzo – the other is Umzimkhulu. Umzimvubu’s population is just 198 550, of which only 4% live in towns – the rest live in rural areas.

Safe drinking water is a continual problem as the area lacks essential infrastructure, including water on tap. Villagers are often forced to dip into natural springs, running the risk of picking up water-borne disease.

“We have a challenge … because about 40% of our community here does not have basic water,” said Alfred Nzo mayor Gcinikhaya Mpumza.

However, the villagers’ lives have changed with the installation of the water-harvesting system and its inexhaustible supply. No electricity is needed to power the scheme, which makes it eco-friendly and low-cost, and suitable for areas with no power infrastructure.

Because the technology is simple, the equipment does not need special maintenance. The system consists of a double layer of 30% shade cloth nets stretched between steel cables supported by posts, with a gutter beneath each screen to catch the run-off. All components are readily available in the area.

The Cabazane set-up involves around 700 square metres of netting, said Olivier, with each square metre of shade cloth yielding up to five litres of water a day – depending on the weather.

Water droplets in the fog are trapped on the nets. They get bigger and heavier as the fog rolls along, and eventually run down into the gutter and from there through a filter into storage tanks. The system works best when the wind is blowing, because the fog moves over the nets more rapidly.

The system is installed up on the mountain slope, where nothing more than gravity is needed to get the drops flowing into the tanks. Reports say that about 30 homes in Cabazane Village have already benefited from the project.

The quality of water is described as “very high”, falling within the World Health Organisation’s standards for potable water. “The water is incredibly pure because it comes from the clouds,” said Olivier.

Innovative schemes like the simple and cost-effective fog harvester are well-suited to South Africa, as it’s one of the driest countries in the world, with annual rainfall well below the global average.

Source: MediaClubSouthAfrica.com

ISSUED BY: THE DEPARTMENT OF WATER AFFAIRS
DATE: 20 January 2010
DROUGHT CONDITIONS PERSIST
The Department of Water Affairs has prioritized support for parts of the
country affected by the prevailing drought conditions due to low rainfall during
last year (2009). According to statistics gathered by the Department, George in
the Eden District Municipality in the Western Cape experienced the lowest 12
consecutive months of rainfall since 1921 and is considered severely dry. The
current conditions started around the month of March 2008.
Having received an annual rainfall of 477mm in the last year which accounts for
only 63 percent of the areas Mean Annual Precipitation (the average amount of
rainfall received annually), urgent measures had to be put in place to deal with
the water shortages including the introduction of severe water restrictions,
sewage water is being re-directed to the purification plants and sea water is
being desalinated to augment supply.
In addition the water storage levels for this area are well below average and
are declining further. The Garden Route Dam: Storage is 30% which is 70%
below the median storage. The Wolwedans Dam: Storage is 37.1% which is 60%
below the median storage and also gradually declining.
Certain parts of the Eastern Cape are under severe pressure and are also
experiencing severe drought conditions; these include Uitenhage under the
Cacadu district municipality, which received a total rainfall of 360mm from
January to December 2009, accounting for only 69 % of its average annual
rainfall. Other affected areas are Grahamstown and Somerset East (Cacadu
District Municipality), Kei Mouth (OR Tambo District Municipality) and Hogsback
(Chris Hani District Municipality) as well as Phalaborwa in the Limpopo
province.
Mava Scott, spokesperson for the department says the Minister’s visit to areas
like Adelaide and Kuruman this week was part of a nationwide drive to find
creative solutions and interventions in the short to long term provision of water
to these communities. “these interventions include soliciting funds to
commission drilling for water/boreholes in the short term, recycling of sewage
water in the medium term but also very importantly the upgrading of the
existing water schemes” he said.
The delivery of water tankers to villages who experienced severe water
shortages in December in the Zeerust area by the Minister constituted one of
these measures to respond urgently to the drought conditions.
Also of critical importance was the issue of water conservation and demand
management especially in these drought stricken areas. Mr Scott added that
consumer behavior in the use of water can go a long way in addressing the
issue of water provision to the communities.
During the 2009 year most parts of the country received normal to above-normal
rainfall with the exception of the southern parts of the Western and Eastern Cape
Provinces, the western parts on the North West Province, the south-eastern parts of
the Limpopo Province and small areas over northern KZN.
The Department of Water Affairs is closely monitoring the situation. Interventions are
being implemented and finalized in other areas. Water Conservation and Demand
management initiatives have been ongoing and these will be intensified.

Dire water shortages from rivers running dry in the Eastern Cape and the central and southern part of the Western Cape, in what AgriSA terms the “worst drought in 130 years”, have focused attention on the lack of regional infrastructure plans and a regulating authority to oversee water pricing.

Emergency measures have had to be taken, including trucking in water and a planned desalination plant at Knysna to avert a disaster facing mainly dairy and vegetable farmers, who have dedicated supply lines to retail outlets but have cut back on their production. AgriSA Western Cape chief executive Carl Opperman said: “This will have a ripple effect down the supply chain ultimately.”

AgriSA predicted that countless farmers were facing insolvency in the coming year. It blamed this on years of neglect of infrastructure with no significant dams being built for lean times, as well as departmental dilly-dallying on allowing farmers to raise farm dam capacity.

At present, Water and Environmental Affairs Minister Buyelwa Sonjica determines water prices after negotiating with water boards, which sell water to municipalities. The argument is that an independent water regulator would provide the platform for realistic prices.

Opperman said a number of southern Cape rivers running from the Outeniqua Mountains ran into the sea within six hours of rain falling in the catchment area. This water could otherwise be stored.

For example, the Ernest Robertson Dam on the Groot Brak River near George in the southern Cape is 90 percent full but its capacity is just 0.4 million cubic metres. The Wolwedans Dam on the same river, with a capacity of 25 million cubic metres, is 39 percent full, down from more than 90 percent a year ago.

The Garden Route Dam on the Swart River has a capacity of 9 million cubic metres but is now only 30 percent full, down from 92 percent a year ago, according to the Department of Water Affairs.

While the department said consideration was being given to new dams in Transkei and the southern Cape, the small size of the latter’s existing dams could be measured against Cape Town’s main supply dam, Theewaterskloof on the Riviersonderend, which was 92 percent full and had a capacity of 480 million cubic metres.

Cornelius Ruiters, the water affairs deputy director-general, said there was an argument in favour of setting up regional water regulatory authorities similar to those in water-stressed countries such as Australia and Mexico.

Nick Segal, a former head of UCT’s business school, has written a report on water stress for Business Leadership SA and estimates that there is a R100 billion backlog in spending on water infrastructure.

Meanwhile, Reuters reported that water was being pumped from the Orange River from a tunnel at Gariep Dam in the Free State into the Fish River to ensure appropriate supply for the Nelson Mandela Bay Metropole in the Eastern Cape.

The metro includes Despatch, Port Elizabeth and Uitenhage, which house major motor plants. They would normally be suffering severe water shortages were it not for diverted water caught in the Lesotho Highlands.

The most affected southern Cape towns include George, Knysna, Wilderness and Plettenberg Bay.

Business Times Cape Times Donwald Pressley