Dossier, Volume 13 #5, Development: Small Steps

Collecting Mists from the Earth

Lakes and rivers, wells and the sea--these are the sources of water most people would list if asked. Initially, though, the water in all these reservoirs comes from precipitation. And even this isn't the total answer, since there are also small contributions from dew and frost, and a larger hidden contribution from fog. For centuries people have known that trees collect the tiny water droplets that make up fog. This covert water input in the mountainous and coastal regions of our planet was called "occult precipitation" in the last century, and the terminology persists in some of the literature to this day.

The ever-growing need for fresh water in both developing and developed countries is indisputable, and both increasing populations and the contamination of existing supplies will lead to constantly escalating demands. As a result, we need to start considering the use of nontraditional water supplies such as the collection of fog. As clouds move over hills and mountains, the hilltops and ridgelines are enveloped in fogs. Just as the leaves and needles of trees can collect some of the water in these fogs, large artificial collectors, made of polypropylene mesh, can produce a flow of potable water.

This simple technology has its roots in antiquity. But there went up a mist from the earth, and watered the whole face of the ground (Gen 2:6). Is this a reference to fog? Some commentators think so. He holds in check the waterdrops that filter in rain through his mists (Job 36:27). In our desert projects, we work in fog but there is no rain. Is this the type of situation that the author of the book of Job was describing? Two thousand years ago, Pliny the Elder wrote about the Fountain Tree, or Holy Tree, on the island of El Hierro in the Canary Islands. From that time to at least 1800, the inhabitants obtained much of their water from fog that dripped from the leaves of one or more trees. In 1776 Gilbert White in England made astute observations on how trees collected water from the "swimming vapours" of fog.

Chungungo is a fishing village on the arid northern coast of Chile. In 1987, in the mountains a few kilometers inland, a project began to investigate the science and technology of fog collection. In 1992 a pipeline was completed and the fog water, from seventy-five collectors each measuring 48 square metres, began to flow down the mountain to Chungungo. The average daily production is 11,000 litres--enough to provide each of the 340 villagers with more than 30 litres.

The water supply has changed the inhabitants' lives, broadened their diets and enriched the community. The villagers now have their own water authority, charge for the water consumed and maintain the lower part of the water system. Periodic surveys of the villagers have shown that they prefer the taste and availability of the fog water to the more expensive trucked-in water they depended on before.

The Chungungo project was a joint Chilean-Canadian effort, involving the Pontifical Catholic University of Chile, the University of Chile and the Chilean National Forestry Corporation. Most of the funding for the project came from the International Development Research Centre (IDRC) in Ottawa, with substantial support also from Environment Canada and the Canadian Embassy in Santiago. The knowledge gained in this project fed into my work in Canada on acidic deposition from fog. In turn there was a flow of knowledge and instrumentation into Chile and other countries. I have subsequently worked on fog projects in Oman, Peru and Ecuador. Funding sources have varied, but IDRC and the Canadian International Development Agency (CIDA) have been involved in many of them.

A fog collection project has just been completed in Ecuador at Pululahua north of Quito, and a new project is underway at Pachamama Grande, an indigenous community in the south of Ecuador at an elevation of 3,700 metres. The local people are participating in the project from the beginning and are delighted at the prospect of having a clean water supply. This is the first project where private-sector donations have played a major role in funding the fog water supply for a village. Volunteers from a Canadian NGO, the Centre Canadien d'Étude et de Coopération Internationale, are working with the villagers and will implement the project. IDRC is funding the initial technical evaluation of the site.

In the complexity of a project, it is sometimes easy to lose sight of the simplicity of the water source and how basic water is to the needs of the people. But there are moments when the villagers themselves bring one back to reality--when they call the spinning cups of the anemometers "butterflies" or when they tell you that even the animals get sick from drinking from the little canal by the village.

Fog collection will not be the total answer to the world's water shortages. However, it is an example of how we can work with what nature gives us and of how developing and developed countries can pool their skills to initiate low-technology water projects that are sustainable over periods of hundreds of years.

Robert Schemenauer is a research scientist with Environment Canada in Toronto.