The New Green Economy

The Chungungo Expirement

Fog harvesting has already proved to be a viable means of freshwater collection in a number of countries where conventional freshwater sources such as wells, lakes, rivers, and pipelines are unavailable.  Robert Schemenauer and Pilar Cereceda have conducted extensive research throughout South America and other parts of the world with fog collection technologies.

Schemenauer is an Emeritus Research Scientist with the Department of Environment in Canada and  Cerceceda is a professor of geography at the Pontifical Catholic University in Santiago, Chile.  Both played an instrumental role in one of the world’s first successful fog harvesting experiments in the remote Chilean fishing village of Chungungo.

Chungungo is located in one of the planet’s driest regions—the Atacama Desert—and receives an average of less than 5cm of rainfall annually.  Before the arrival and implementation of fog collection technologies in 1992, the village’s inhabitants relied on water delivered from distant wells, a process that proved to be both expensive and unhealthy as the water was often contaminated.

Six years later, with the help of 80 fog collectors, village residents were enjoying an average of 10,000 liters of fresh drinking water each day—an estimated 35 liters per individual.¹ Consequently, the quality of life in Chungungo improved dramatically as the freshwater boom lead the village to flourish.

"This project was always designed to supplement the existing water supply, which was trucked-in water,” opined Cereceda on the success of the project.  “But during the first year of the project the truck did not have to come to the village. Even during exceptionally dry years, the truck has only had to come from time to time. So now we believe that the main source of water for this area is the fog collectors.”²

"We are always going to need some way to solve water problems for rural villages, isolated villages, and clusters of remote homes in the uplands of developing countries,” commented Schemenauer.  “That's how the fog collector projects got started, by trying to solve water problems that couldn't be solved any other way."³

Desert volleyball?

At a glance, a typical fog collection site resembles an oversized beach volleyball court: two poles standing perpendicular to the ground with a rectangular, mesh net in between.  The net is designed to trap tiny water droplets as prevailing coastal winds blow fog inland.  Gravity then takes over, causing the accumulated droplets to pass through gutters that lead to a reservoir.

An average fog collecting net covers a surface area of 48m² and is may result in anywhere from 150 to 750 liters of freshwater production a day.  At about $400 USD per net, which is usually subsidized by international aid organizations, the cost of fog harvesting makes it accessible to virtually any community that meets the proper meteorological, geographic, and societal conditions.

Schemenauer and Cereceda note these conditions must be met if the technology is to be a success.  Prerequisites include an in-depth study of regional wind patterns and the presence of a nearby mountain range to intercept fog cover carried by the prevailing winds.  The candidate community must also be one that is unable to meet its water needs with existing freshwater supplies.⁴

Other international projects

In observance of the Republic of South Africa’s National Water Week and the U.N.’s World Water Day, a new fog harvesting project was recently launched in the South African Cabezane Village, located in the Mount Ayliff region of the Eastern Cape Province.  The project was lead by University of South Africa (UNISA) climatologist Jana Olivier, along with Johan van Heerden, Hannes Rautenbach, and Tinus Truter of Pretoria University.

Olivier and her colleagues received funding for the project from the South African Water Research Commission.  UNISA has spearheaded similar projects in other arid regions of the country, but claims enormous success in Cabezane Village, thanks to heavy amounts of fog that roll in over Mount Ayliff.  Olivier reported the water quality as “very high”, meeting the World Health Organization’s standards for drinkable water.

The South African water conservation group Water Rhapsody responded enthusiastically to Olivier’s work: “We are so thrilled with the new fog collection technique being developed and deployed around rural South Africa. At least all South Africans can have a chance of having fresh clean water without having to walk miles to get it. Rainwater cannot be harvested off a thatch roof which is often the case for houses in rural SA [South Africa]. What a great revelation to arrive just in time for World Water Day.”⁵

REFERENCES

¹http://www.idrc.ca/en/ev-26965-201-1-DO_TOPIC.html2

²http://www.idrc.ca/en/ev-5077-201-1-DO_TOPIC.html

^3,4http://www.tiempocyberclimate.org/portal/archive/issue26/t26art3.htm

⁵http://www.watersense.co.za/2010/03/22/water-harvested-from-clouds-in-rural-south-africa/