Peruvians harvesting water from fog
When dense fog sweeps in from the Pacific Ocean, special nets on a hillside near Lima, Peru, catch the moisture and provide precious water to an area that gets very little rainfall–about half an inch (1.5 centimeters) a year.
The nets stand perpendicular to the prevailing wind, which blows fog into the coarse, woven plastic mesh. From there, drops of fog-water fall into gutters that carry the water to collection tanks.
Since 2006 the nets–built by German conservationists Kai Tiedemann and Anne Lummerich–have helped provide the village of Bellavista, 10 miles (16 kilometers) south of Lima, with hundreds of gallons of water each day during the foggy winter months of June to November. (nat.geographic news)
Pure water from fog
Catching fog with nets is the solution to water scarcity for people who live beyond the reach of utility lines like here in Bellavista, a sandy hillside shantytown overlooking Peru’s capital, Lima.
Lima, which along with Cairo is one of the world’s two driest capitals, gets only a few drops of rain each year. But thick fog from the Pacific Ocean blankets the coastal hills surrounding the city for eight months a year as hot tropical sun mixes with cold waters of the Humboldt current.
Using nets similar to those used in volleyball, residents condense fog, drip-by-drip, into drainage pipes running down the hill into tanks that store hundreds of liters of water for irrigation, bathing and cooking.
“Pure water from fog, can you believe it?” Noe Neira, Bellavista’s community leader said, as he dipped his hand into a brick tank filled to the rim. “There was so much water in the air and we didn’t know how take advantage of it.”
Lima depends almost exclusively on glacial runoff for water. The United Nations says melting caused by warming in the Andes has already cut by 12 percent flows to the country’s arid coast, where two-thirds of the population lives.
That has left the government not only trying to lay more water mains to improve delivery, but also looking into installing desalination plants along the ocean or pumping water out of the Amazon basin to secure future supplies.
Even after a decade of booming economic growth, about a quarter of Peru’s city dwellers and half of its rural residents still lack access to working toilets and clean drinking water.
In this area mostly poor people of Lima live. They are the bus drivers, street vendors and construction workers … those who can’t afford to live in the city.
They live high up in the hills. It is cheap, only they have to worry about landslides—not to mention there’s no water. Rain hardly ever falls here, and only the city people get water from the Andean lakes.
Still, the hill people got lucky when Kai Tiedemann and Anne Lummerich came along. They’re German conservationists who run a small development called Alimon. In 2006 they began helping the people of Bellavista to set up special nets that soak up water directly from the air.
When the wind blows the fog through the coarse woven mesh, the droplets stick. As more and more droplets hit the net they clump together and form drops. Next, they fall into a gutter and flow through tubes into the gathering pools. The pools can hold up to 25,000 gallons of water. One net can hold as much as 150 gallons.
The villagers now grow a tree with fruit that is used for treating furniture leather. The money they make from selling the fruit helps to pay for maintaining the nets.
This is not the only place where people catch fog. In the north of Chili they use a tent-like construction, also giving a lot of clean water. The system is very ecologically sound as we are simply taking advantage of moisture that would otherwise be lost into the atmosphere. It has virtually no negative impact on the ecosystem, is economically viable, and is eventually left in the hands of the local users to manage and maintain.
In the initial phase of a project, they used a standard fog collector so that they could compare productivity in different areas. If good results are produced, the next step is to install larger collectors to maximize the water collection. In some areas, tthey have arrays of 100 collectors.
Fog is created as a result of an area’s topography and proximity to bodies of water, most prevalent in coastal regions. Some regions that experience a lot of fog are also some of the most arid places on the earth receiving little or no rainfall. It is here that this technology is most appropriate. The fog collectors require fog that has a high moisture content, that being convection fog.
The fog collectors can also be incredibly efficient at capturing rainwater, increasing the number of potential sites.
Fog collectors can go anywhere, even on top of buildings. Wherever there is a relatively clear area free of trees (so there is more wind and cloud) is a good spot. They usually go in smaller villages to provide water for agricultural irrigation, water for animals, and drinking water.
Namib beetles catching water >
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Humans are not the only inventors of fog catching. Many species of plants live by water from the air. But also animals know the trick. Most famous is the fog catching beetle in Namibia that uses the same technique as the Chileans. The beetles stand half upright in a position that the condensed water runs in its mouth.
The Atacama Desert is the driest place on the planet and many believe that agriculture is almost impossible on this land. But then modern designers along with their creativity and technological brilliance are making the impossible possible. This is being done by harnessing water from the mist clouds that hover above the desert edge with a structure that is almost like a magic site out of an ancient land.
We go to the northern coast of Chile, where Alberto Fernandez and Susana Ortega have conceived of a Fog Tower that absorbs and channels water from its mist enshrouded environs. This pristine helical structure would allow for the development of a sustainable agriculture environment at the edge of the Atacama Desert, one of the driest places on earth.
One of the most promising approaches to sustainable architecture is the design of structures that benefit from the unique profile of their immediate environment.
The structure looks magical and almost impossible actually. The Coastal Fog Tower is highly specialized in this approach, utilizing a type of fog unique to Chile called “camanchaca“. Standing 400 meters tall, Fernandez and Ortega’s seaside spire is a cloud catching marvel that stands to harvest airborne water molecules in the Huasco River valley. The Fog Tower is like an inverted screw, to put it in a simple fashion, and is amazing to watch.
More than the structure, it is the idea and the implementation of it that are commendable. The end result is a water distribution system with a planned performance of 2-20 liters per square meter of vertical surface, producing from 20,000 to 200,000 liters of water per day. This structure is a tribute to green designing and architectural brilliance. It shows what we can do when we amalgamate imagination with ingenuity.