The fog harvest could provide water for drier cities

Capture the water from the fog, on a large scale, could provide some of the driest cities in the world with drinking water.

This is what researchers in Chile have concluded after studying the potential of fog collection in the city of the Desert of Alto Hospicio in the north of the country.

The average rain in the region is less than 0.19 inches (5 mm) per year.

“The city also has many social problems,” said the principal researcher, Dr. Virginia Carter Hamberini, of the Mayor of the University. “Poverty, drugs, many low neighborhoods.”

Without access to water supply networks, people in low neighborhoods trust drinking water that is delivered by the truck.

However, fog clouds that regularly gather on the mountain city are an unspecified source, the researchers say.

Capture fog water is remarkably simple: a mesh between the posts is hung, and when the clouds loaded with moisture pass through that fine mesh, drops are formed. Water is channeled to pipes and storage tanks.

It has been used on a small scale for several decades, mainly in the rural south and in Central America, in places with the appropriate fog conditions. One of the largest fog water collection systems It is in Morocco, on the edge of the Sahara desert.

However, Dr. Carter says that a “new era” of the collection of large -scale fog on a larger scale could provide a safer and sustainable water supply in urban environments where it is most needed.

She and her colleagues carried out evaluations of how much water can be produced by collection of fog, and combined that information with cloud formation studies in satellite images and with weather forecasts.

From this, they concluded that the clouds that are formed regularly on the Pacific, and are flown in the coastal city of the mountain, could provide the people of the marginal neighborhoods of Alto Hospicio a sustainable source of drinking water. They published their findings in An article in the magazine Frontiers of Environmental Science.

The Alto Hospicio fog is formed on the Pacific Ocean, when warm and humid air flows on cold water, and then blows on the mountains. The conditions reliably nebulous here allowed Dr. Carter and his colleagues to identify areas where the highest volumes of water could be harvested regularly from the clouds.

According to an annual average water collection rate of 2.5 liters per square meter of mesh per day, the researchers resolved:

• 17,000 square meters of mesh could produce enough water to meet the weekly demand of water of 300,000 liters that is currently delivered by truck to urban marginal neighborhoods
• 110 square meters could meet the annual demand for irrigation of the green spaces of the city
• Fog water could be used for free agriculture (hydroponic) without soil, with yields of 33 to 44 pounds (15 to 20 kg) of green vegetables in a month

Alto Hospicio is on the edge of the Atacama desert, one of the driest places on Earth. With little or no precipitation, the main source of water in the cities in the region are underground aquifers, layers of rocks that contain spaces full of water, which were filled for the last time thousands of years ago.

With urban populations that grow and the demand for these mining and industry water supplies, scientists say there is an urgent need for other sustainable sources of clean water.

Dr. Fiamerini explained that Chile is “very special” for its marine fog “, because we have the ocean throughout the country and we have the mountains.”

Currently, his team is working on a “fog collection map” from all over the country.

“The water of the clouds,” as Dr. Carter describes, he could, he said, “to improve the resistance of our cities to climate change, while improving access to clean water.”