Key points
- Fog is a cheap and abundant source of fresh water
- Fog harvesting has great potential for cities
- Average of 2.5 litres of water could be harvested per day
ISLAMABAD: Capturing water from fog – on a large level – could provide some of the driest cities across the world with drinking water.
This is what scientists in Chile have concluded following studying the potential of fog harvesting in the desert city of Alto Hospicio in the north of the country, BBC reported.
According to BBC, average rainfall in the region is less than 0.19in (5mm) per year. “Like a lot of cities, Alto Hospicio has its social issues,” said lead researcher Dr Virginia Carter Gamberini, from Universidad Mayor. “There is a lot of poverty”, she explained, and many people there have no direct access to the networks that supply clean water.
City’s poorest areas
Many who live in the city’s poorest areas rely on drinking water that is delivered by truck. BBC cited the researcher as saying that clouds of fog that regularly gather over the mountain city are an untapped source, researchers say.
Sitting on the fringes of the Moroccan desert, the mountainous region of Ait Baamrane receives little rainfall. But what it does get in abundance, and for six months of the year, is dense fog sweeping in from the nearby Atlantic Ocean, according to DW. While it might restrict visibility, this misty mass also provides a solution to water shortages in the region.
How does fog harvesting work?
DW reported that wind pushes water vapor in the air through vertical nets, where it condenses into small droplets that trickle down the netting to be gathered in large containers. The nets collect around 35,000 liters of water daily, which covers the needs of over 1,000 people and is also used to irrigate plants.
Fog is not only collected in Morocco’s mountains but in other places including Eritrea, Ghana, Chile, California, Ethiopia, and South Africa, German media reported. The global potential is huge with suitable locations almost everywhere, especially along coastlines.
Depending on the location, a 40-square-meter fog net provides around 200 liters per day. Each one costs around $1,500.
Can cities also benefit?
Until now, fog collection has mainly been seen as a solution for remote rural areas where citizens are barely connected to the public water network or infrastructure.
However, a study recently published in the scientific journal Frontiers in Environmental Science claimed that the technology could also benefit cities.
Meeting slums’ water needs with fog
According to researchers, an average of 2.5 liters of water could be harvested per day and square meter. Using 17,000 square meters of netting, the size of around two and a half soccer pitches, would make it possible to cover the entire water requirements of the slums of Alto Hospicio.
Around 110 square meters of netting would be enough to irrigate the city’s entire green spaces all year round.
Water harvested in this way could be shifted further via pipes or by truck. However, as the fog only supplies water for a few months of the year, residents would have to rely on other sources in the summer months, according to DW.
