Cultivating fog for water? The Canary Islands are operating a new reservoir.

Since 2018, when rain is scarce during the summer months, Jonay González Pérez and Sara Rodríguez Dorta have relied solely on fog to water their 3.7 acres of farmland.

On a good day, the couple’s collector wall — vertical U-shaped nets cemented into the ground by metal posts — can harvest 475 gallons of water from the fog. Suspended mist droplets fall from the nets and flow through 220 meters of black tubing into a 95,000 gallon storage tank that looks like a giant waterbed.

Why we wrote this

Lack of usable water is becoming a problem in areas where there was none before, due to climate change. But in the Canary Islands, locals are finding that the fog can make up for shortages on farms.

“We are in an area where the local authorities do not provide water for agricultural use,” explains Mr. González Pérez. “So without the fog collectors, our farm just wouldn’t exist.”

As the Canary Islands and parts of the world seek to combat the effects of climate change, fog collection is becoming an increasingly viable technology for communities facing soil erosion and water supply issues. .

“Basically, we depend on our groundwater in the Canary Islands, and water is always scarce,” says María Victoria Marzol Jaén, a retired climatologist. “Mist water alone cannot provide this. … But for rural areas, where water consumption is much lower, [fog collecting] is more than helpful. This can be the solution to water problems.

On a clear day, the tiny hamlet of La Vega, stacked on the hills of northern Tenerife, offers spectacular views of the rugged Atlantic coastline. But this afternoon, the thick mist sweeping through the farmlands of Jonay González Pérez and Sara Rodríguez Dorta creates a bizarre Alfred Hitchcock cinematic scene.

Almost ripe for fog harvesting.

“There’s almost enough fog to start picking it up,” said Mr. González Pérez, trudging through ankle-deep grass in rubber galoshes while breaking dead leaves from an artichoke plant. “But we have to wait a bit longer, until the fog is level with the receiver.”

Why we wrote this

Lack of usable water is becoming a problem in areas where there was none before, due to climate change. But in the Canary Islands, locals are finding that the fog can make up for shortages on farms.

Since 2018, Mr. González Pérez and his wife have relied solely on fog collection to water their 3.7 acres of farmland – which includes lemon and plum trees, artichoke plants and 50 chickens – when the rains come. rare during the summer months.

On a good day, the couple’s 435-meter-long collector wall – U-shaped vertical nets cemented into the ground by metal posts – can harvest 475 gallons of water. Hanging mist droplets fall from the nets and through 220 meters of black tubing, which winds around the back of their property in a 95,000 gallon storage tank that looks like a giant waterbed.

Their system – which the couple built with their bare hands over a year – was funded entirely by government grants, having won a local award for best rural farming initiative.

But it’s not just a favorite project for small-scale farmers. In 2020, the European Commission partnered with the local government of neighboring Gran Canaria to fund the Life Nieblas fog collection project, which aims to reforest areas decimated by drought or forest fires. The harvested fog water meets World Health Organization standards for drinking water safety and has provided remote communities with a much-needed resource for decades.

Jonay González Pérez shows off some of his fog collectors in La Vega, Spain, October 26, 2022. He and his wife, Sara Rodríguez Dorta, rely on fog to water their 3.7-acre farm.

As the Canary Islands and parts of the world seek to combat the effects of climate change, fog collection is becoming an increasingly viable technology for communities facing soil erosion and water supply issues. .

“Basically we depend on our groundwater in the Canary Islands and water is always scarce,” says María Victoria Marzol Jaén, a retired climatologist at the University of La Laguna in Tenerife and one of the pioneer researchers in collecting of fog in the Canary Islands. in the 1990s.

“Fog water alone cannot provide this, but it can be useful for reforestation purposes, such as in the case of wildfires. But for rural areas, where water consumption is much lower, [fog collecting] is more than helpful. This can be the solution to water problems.

“We have a natural resource right in front of us”

The first documented experiments with fog as an alternative water resource date back to South Africa in the early 1900s. In 1963, Chilean physicist Carlos Espinosa’s invention of “fog traps” was patented and gifted to UNESCO for free use worldwide. Since then, researchers have made significant developments in green technology and research sites are in Chile, Peru, South Africa, Morocco, China, the United States and the Canary Islands of Spain. .

Due to their high altitude and abundance of fog – in addition to their unique water supply challenges – the Canary Islands have remained at the center of fog harvesting research, especially Tenerife and Gran Canaria .

Although there are slight variations, most fog collection systems follow a pattern similar to that built by Mr. González Pérez and his wife, involving two or more nets that catch the fog droplets, which then drip off in a waiting container.

In addition to the initial materials and construction costs, fog collection is a low-energy operation, whose structures, such as nets, can fit more seamlessly into natural environments than wind turbines or panels. solar. Maintenance consists simply of removing invasive plants and cleaning the filters.

“Collecting the fog does not consume energy and does not affect any other natural resource,” explains Ricardo Gil, technical architect in Tenerife who runs the Nieblagua company. He has installed around 100 fog collectors in the Canary Islands, mainland Spain and Portugal. “It also reduces the pressure on extracting water from aquifers or desalinating water from the oceans.”

Each of Nieblagua’s collectors can withstand winds of up to 62 mph and use four sheets of netting to collect up to 8,000 gallons of water per year under optimal conditions. In several of the Canary Islands, which enjoy around five hours of fog a day, this translates to almost one person’s water needs – the World Health Organization estimates that between 50 and 100 liters (13 to 26 gallons) of water is needed for a person’s basic daily use.

For parched and drought-stricken regions, this can be the difference between survival and desertification, especially when multiple sensors are installed in an area. In Arafo, Tenerife, 12 fishermen from Nieblagua supply around 26,000 gallons a year to new almond plantations.

“It’s not a fantasy. All over the world, we are depleting our natural resources,” Gil says during a coffee break in La Laguna. “Here we have a natural resource right in front of us. You should take advantage. »

“Very useful on a small scale”

Fog is often referred to as “horizontal rain”, but collecting it has its limits and depends on certain conditions to work. There should be enough wind to push the droplets through the nets, but not so much that it knocks the whole structure over. And, of course, there must be enough fog.

This 95,000 gallon storage tank conserves fog water on Jonay González Pérez and Sara Rodríguez Dorta’s farm during the summer months when rain is scarce.

In recent years, weather patterns have become more erratic due to climate change, making the quantity and quality of fog periods more unpredictable and, therefore, less reliable with respect to harvesting efforts.

“Fog collection can only be done under very specific conditions. Mountain ranges are the best,” says Axel Ritter Rodríguez, professor of agroforestry engineering at the University of La Laguna and researcher of the Life Nieblas project. “I don’t think it’s the cure for all our water problems, but it’s very useful on a small scale.”

The Life Nieblas project took this reduced approach, but with a broader vision for the future. Project members installed 15 of the Nieblagua sensors in Gran Canaria with the aim of harvesting 57,000 gallons of fog water in one year to repopulate 86 acres of the Doramas forest with 20,000 laurels. The region is at high risk of desertification due to forest fires.

The Life Nieblas researchers are also developing a separate system that resembles a wind tunnel “to contribute to our knowledge of fog collection,” says Dr. Ritter Rodríguez.

As the Canary Islands and the Spanish peninsula look to the future, they can expect more erratic and intense periods of rain, in addition to an increase in extreme weather events such as heat waves and storms. , explains Jorge Olcina Cantos, geographer at the University of Alicante. . “As far as temperature goes, it’s going to get less comfortable,” he says.

This has made new energy efficient technologies even more important when it comes to finding solutions for water. Research is also continuing on dew collection, which uses a similar system of capturing condensation via horizontal nets.

The overriding goal is to stay ahead of the game, which means anticipating water and soil needs before they become a problem. Mr. González Pérez and Ms. Rodríguez Dorta knew this when they started as young farmers five years ago. Even though their soil is intended for growing apple and pear trees, they decided to plant lemon trees instead, which benefit from a more arid climate.

“We spent about a year thinking and planning this farm. When we bought the land, there had just been forest fires 100 meters away [109 yards] away that had destroyed the area,” says González Pérez. “We could already see that climate change was going to affect things in the future. … We are in an area where the municipality does not provide water for agricultural use. So without the fog collectors, our farm simply wouldn’t exist.

About Keneth T. Graves

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