SDG 15 | terrestrial ecosystem life
Gran Canaria is working on a fog catcher system to make vegetation grow without wasting water resources
“The mist of the water is a godmother.” This is how the Spanish proverb sentences it, which for each situation in life has a mention. Its big brother, fog, is the suspension in the air of very small drops of water at ground level that reduces visibility to less than a kilometer. If it does not limit that vision, “we must speak of fog or mist,” say meteorology experts.
A very common phenomenon in the autumn and winter months when the small drops of water present in the environment condense after suddenly coming into contact with a surface or a cold air current. They are low clouds that are located at ground level and usually disappear with the sunrise and rising temperatures.
A silent rain that wets streets and fields and that is becoming increasingly important due to the lack of precipitation in recent years. The first third of the hydrological year, between October 1, 2021 and January 31, 2022, will probably be “one of the driest” in the last sixty years and will be among the five with the least rainfall this century, according to the State Meteorological Agency (Aemet). The previous one, closed on September 30, ended with an accumulated precipitation 17% below the average. However, these water balances do not reflect the importance of fog on the ground.
An interest that they have captured in the Canary Islands. “The collection of fog water in the Canary Islands is something traditional and comes from pre-Hispanic times, from the Canarian aborigines,” recalls Rainero Brandon, coordinator of Life Nieblas of the Cabildo de Gran Canaria. “These used the capture of water through vegetation, especially trees, to supply livestock and the population,” he adds. His weapon, the Garoé tree, typical of the Iron Island.
Over the years, the technique has evolved and “the first collection systems arrived in Tenerife in the 70s,” says Brandon. The Canarian seas of clouds, a typical Canarian meteorological phenomenon, formed at 500-1,500 meters of altitude are the great allies to hunt the tiny drops of water of these clouds.
“We use the Chilean catchment system,” explains Rainero Brandon. In the 1960s, the physicist Carlos Espinosa managed to hunt down Chilean clouds to ‘water’ the Atacama desert, the driest non-polar place on Earth. The abundant mists, created by the proximity to the Pacific Ocean, are the great water resource of the region, where there can be up to 40 years of waiting between periods of rain.
cloud chasing
“It’s very basic technology,” says Brandon. A large mesh, a frame for its support, a gutter and a collector pond. This is the list of materials that Espinosa, together with Israeli technicians, implanted in Chile. “We have evolved the technique a little more,” adds the Canarian expert.
In 2008, the agricultural engineer Theo Hernando Olmo devised and patented three-dimensional fog, dew and precipitation sensors. “The mist passes through the mesh, condenses and the water falls into the bucket,” he simplifies. With this new premium shape design, the system has higher stability, higher capture power and less space occupation. “We have tried to maximize efficiency,” he adds.
Structure of a
standard fog catcher
TO. Clouds traverse network.
b. By condensation, the drops
of water they stay between
mesh threads.
c. The drops they fall still receiver
what is at the bottom.
d Through the pipes come
to bottles or small ponds
to store them and then
use it for reforest.
Structure of a standard fog catcher
TO. Clouds traverse network.
b. By condensation, the drops
of water they stay between
mesh threads.
c. The drops they fall still receiver
what is at the bottom.
d Through the pipes come
to bottles or small ponds
to store them and then
use it for reforest.
A work that for a year and a half has become a reality in Gran Canaria to see it sprout again. The island council leads the Life Nieblas project to repopulate 33 burned hectares with a high risk of desertification with 20,000 laurel trees. “It’s not just capturing water, but reforesting without CO2 consumption,” says the project coordinator.
The Canary Islands are the testing ground for an unprecedented plan that brings together the efforts of the Cabildo, the public company Gesplan, the Canary Institute for Agricultural Research, the Canary Islands Technological Institute, the University of La Laguna, the Heredad de Aguas de Arucas and Firgas, the Center for Ecological Research and Forestry Applications of Catalonia and the Viseu Dão Lafões Intermunicipal Community of Portugal.
The challenge now is to transform a space that has undergone centuries of logging and massive extraction of water from aquifers, where 90% of the soil is subject to great water stress. “The rainfall regime is decreasing and the vegetation needs water help,” warns Rainero Brandon. “Before irrigation was not needed and in recent years continuous irrigation has had to be done for them to survive,” he adds.
“The temperature throughout the Canary Islands is continuously rising, as indicated by the existing records since the mid-20th century,” point out researchers from the University of La Laguna, Francisco José Machín and Aridane González González. In addition, the archipelago closed the 2020-2021 hydrological year below the normal standard, according to the State Meteorological Agency (AEMET). “Every time we are going to have less water,” adds the coordinator of Life Nieblas.
Reforest Gran Canaria
Since April 2020, the Canarian reforestation project has managed to slow down the desertification of the Barranco de la Virgen with the planting of 3,000 laurel trees irrigated with water from the fifteen fog catchers installed on these slopes. “We hope to carry out reforestation without the need to add water resources,” he details. “We have a standard average collection per device that would be between 15,000 and 35,000 liters per year, although it depends on whether the year is rainy,” he adds.
About to complete the project’s second year of life, Life Nieblas continues with its roadmap to reach 20,000 trees in 2024.