Air/Fog Harvesting 

Introduction

This practice is also sometimes referred to as "cloud fishing".

Investigation of ancient water infrastructure shows that we may have been using air harvesting practices long ago. These includes a cave along the Silk Road with a pile of stones which held enough liquid precipitate into water, to feed the camel trains.

It is also possible that Dew Ponds rely on atmospheric water to recharge.

On this page we explore some modern solutions which are being tested along coastlines and already providing farmers with water.

According to a South African case study, "Small, local solutions can crack water crises"

Prevention

When we avoid overconsumption of products that consume the most water, we can have a greater, and longer-lasting impact that small, at home changes. 

Learn about which activities use the most water, to develope a plan on curring your own water footprint. In many cases consuming less will have a greater impact than harvesting water, though water collection may be your first step in your water conservation journey.

Methods of Air/Fog Harvesting 

Air Well (Condensers)

Life Expectancy:  100+ years.

Pro: This can use natural materials, air flow, and humidity to condense water into liquid form using passive air flow. Modern variations have been created with metal roofs and gutters for water collection, with insulation under the roof increasing water collection by about 50%

Con: Requires humidity to work, and huge condensers such as the one shown on the right only produce around 5 gallons of water per night, making them extremely inefficient considering the amount of mining and construction effort to build them.

Solution: Modern versions of condensers work much better, using active components like fans to boost efficiency.

Fuel Types: Passive Air Flow, Humidity

'Fog harp' makes water out of thin air using design improvements over the original inspiration, fog nets. 

Life Expectancy: Unknown

Pro: Passively wicks moisture from humid air. Doesn't strain surface water or aquifers.

Con: Won't work in dry air, may not work in still air. May have unforeseen consequences for other communities by altering atmospheric portion of the water cycle if used on a massive scale.

Solution: Scientists should monitor what if any impact mass implementation may have on the environment and international water cycles.

Fuel Types: Ambient Wind/Air Motion, Water Cycle

Fog Nets 

These rely almost entirely on the presence of frequent fog and wind, with the critical factors of the technology being the fog's density, wind speed, and the material of the mesh. The polypropylene netting collects droplets which can then gather. The combined weight of the droplets pull the water down to be collected in a tube at the bottom of the nets, which direct the water harvest into a pipes which can travel down hill to be drunk or used in farming. 

This can be ideal on desert hillslopes and other dry regions  along coastlines where fog density can be extremely high but other water sources low. Ideal placement for nets are hilltops, where gravity can bring the water into the valley for storage and use. 

Hydropanels

These run on solar power to condense moisture from the air into drinkable water.

Warka Tower

Life Expectancy:  unknown

Pro: Works with passive air flow and humidity to produce potable water. Design at top helps deter birds from perching or pooping on the tower (protecting the supply), and the shade at the bottom is designed to provide a comfortable gathering spot while reducing evaporation.

Con: Relies on fog, dew, and rain.

Solution: Alternative water harvesting methods may need to be included in the community's water security plan.

Fuel Types: Water Cycle - Rain and/or aquifer water+ passive air flow + gravity.

Warka Towers "Locations with high rates of fog or humidity are the best places to install the Warka Tower. The water harvesting capacity strictly depends on the meteorological conditions and the aim is to distribute from 40 to 80 liters (10 to 20 gallons) of drinking water every day for use of the community."

"Warka Tower is designed to harvest potable water from the atmosphere (it collects rain, harvests fog and dew). It functions only by natural phenomena such us gravity, condensation & evaporation and doesn’t require electrical power. Warka Tower is designed to be owned and operated by the villagers, a key factor that will facilitate the success of the project. The tower not only provides a fundamental resource for life – water – but also creates a social place for the community, where people can gather under the shade of its canopy for education and public meetings."

System Additions

Rain Barrels/Butts & Cisterns 

These are generally used to collect rain and snowmelt, however they can also be paired with rooftop air condenser systems, to help store the water for later use. 

Life Expectancy: 20 years.

Pro: Safely stores rain or grey water for later use.

Con: An turn into a breeding ground for mosquitoes, or be contaminated with dead animals that can fall/get trapped inside. I've found dead frogs who might have hatched but not been able to get out. Dead leaves can build up, leaching tannins into the water.

Solution: Install fixtures that will help keep wildlife and leaves out of the system. Make sure to clean these to prevent plugging and backups. Empty and clean out the container periodically.

Fuel Types: Water Cycle + Gravity

Methods That May Use Humidity 

Dew Pools

"A dew pond is an artificial pond usually sited on the top of a hill, intended for watering livestock. Dew ponds are used in areas where a natural supply of surface water may not be readily available. The name dew pond (sometimes cloud pond or mist pond) is first found in the Journal of the Royal Agricultural Society in 1865. Despite the name, their primary source of water is believed to be rainfall rather than dew or mist."

"They are usually shallow, saucer-shaped and lined with puddled clay, chalk or marl on an insulating straw layer over a bottom layer of chalk or lime. To deter earthworms from their natural tendency of burrowing upwards, which in a short while would make the clay lining porous, a layer of soot would be incorporated or lime mixed with the clay. The clay is usually covered with straw to prevent cracking by the sun and a final layer of chalk rubble or broken stone to protect the lining from the hoofs of sheep or cattle. To retain more of the rainfall, the clay layer could be extended across the catchment area of the pond. If the pond's temperature is kept low, evaporation (a major water loss) may be significantly reduced, thus maintaining the collected rainwater. According to researcher Edward Martin, this may be attained by building the pond in a hollow, where cool air is likely to gather, or by keeping the surrounding grass long to enhance heat radiation. As the water level in the basin falls, a well of cool, moist air tends to form over the surface, restricting evaporation." - https://www.wikiwand.com/en/Dew_pond 

Plants to Increase Permeability on Slopes

The following focus more on systems to boost soil permeability, rather than harvesting drinking or irrigation water. By sequestering water within the soil, we can (to an extent) remove the need for irrigation.

Systems such as swales double as a measure to sequester water in the soil, and when full enough, they can help transport excess water to a secondary location such as body of water, a rain garden, or regular flowerbeds.

Earthworks

Key Lines

Swales

Water Recycling 

Grey Water 

Tools & Resources

Guides & Practical Information

Landscaping Know-How

Organizations

International

NGO Supplying Company

Africa

Asia

India

Europe

UK

North America

Mexico

USA


Oceana

South America

Maps

North America

USA

Grants & Funding

Oceana

Australia

Western Australia

Companies

Fog Net Producer