Fog collection can relieve water stress in desert cities

Rural communities in dry regions have harvested small fog drops for years as a source of fresh drinking water. Now, researchers say fog water can be a practical addition to remove water stress for the largest desert cities.

A one -year evaluation of the potential volume of fog water harvested near a city in the AtaCama desert of North Chile revealed that it is possible to gather as much as 5 liters per square meter daily, scientists report February 20th on February 20 Boundaries in environmental science.

Megadrought and poor water management in Chile have placed over 8 million people in the country under water stress. The country faces the threat of repeated absences by 2050, says Virginia Carter Gamberini, a geographer at the Universidad leader in Santiago, Chile and colleagues.

Hundreds of thousands of people living in cities with fast population, dense in the Atacama desert are particularly in danger. Most groundwater in the region is immersed in mines and agriculture. Gamberini and her colleagues focused their analysis in Alto Hospicio, a solution that expands rapidly over 100,000 people on the outskirts of the Iquique provincial capital.

Almost all the drinking water in Alto Hospicio is trucked by aquifer training places 70 or more kilometers away, at the foot of the Andes Mountains. In winter and spring, the region also receives coastal fog moisturizing wafts, called “Camanchaca” or dark, in the local language of Aymara. Low clouds are formed while wet air masses moving south by Amazon meet fresh air over the Pacific Ocean. The fog nourishes the life of the bold desert, including cacti and lichens and algae that reach the rocky land.

The fog collection is simple, though it is usually applied to a much smaller scale: a 1 -square -foot mesh sheet is suspended vertically, opposite the fog -loaded wind. The water is collected in the net and drips in a hose. Researchers found that between 0.2 and 5 liters of fog water could be harvested per square meter a day in places around the city during the foggy months, with greater potential in areas with higher altitudes.

That volume of water is nowhere near itself. Alto Hospicio’s total consumption requirements are about 300,000 liters a week, an amount that would require 17,000 square meters similar to collect. This need is projected to grow as the city grows. But as the water pressure increases, the team says, the fog harvest can provide a little hopeful bloom in the desert.