New ways of harvesting ‘untapped’ source of fresh water being developed

By Stephen Beech via SWNS

New ways of harvesting a huge "untapped" source of fresh water are being developed.

An "almost limitless" supply of fresh water exists in the form of water vapor above Earth’s oceans, say scientists.

A new American study is the first to suggest an investment in new infrastructure capable of harvesting oceanic water vapor as a solution to limited supplies of fresh water in various locations around the world.

Researchers evaluated 14 water-stressed locations worldwide for the feasibility of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water – and to do so in a manner that will remain feasible in the face of continued climate change.

Study leader Professor Praveen Kumar, of the University of Illinois Urbana-Champaign, said: “Water scarcity is a global problem and hits close to home here in the US regarding the sinking water levels in the Colorado River basin, which affects the whole Western US.

“However, in subtropical regions, like the Western US, nearby oceans are continuously evaporating water because there is enough solar radiation due to the very little cloud coverage throughout the year.”

But the research team said that previous wastewater recycling, cloud seeding and desalination techniques have met only limited success.

Though deployed in some areas around the world, desalination plants face sustainability issues because of the brine and heavy metal-laden wastewater produced – so much so that California has recently rejected measures to add new desalination plants.

Kumar said: “Eventually, we will need to find a way to increase the supply of fresh water as conservation and recycled water from existing sources, albeit essential, will not be sufficient to meet human needs.

"We think our newly proposed method can do that at large scales."

The researchers performed atmospheric and economic analyses of the placement of hypothetical offshore structures 210 meters (689 feet) in width and 100 meters (328 ft) in height.

Through their analyses, the research team concluded that capturing moisture above ocean surfaces is feasible for many water-stressed regions worldwide.

They say the estimated water yield of the proposed structures could provide fresh water for large population centers in the subtropics.

The researchers explained that one of the more robust projections of climate change is that dry regions will get drier, and wet areas will get wetter.

Atmospheric sciences Professor Francina Dominguez said: “The current regions experiencing water scarcity will likely be even drier in the future, exacerbating the problem.

“And unfortunately, people continue moving to water-limited areas, like the South western United States."

However, the projection of increasingly arid conditions favors the new ocean vapor-harvesting technology.

Graduate student Afeefa Rahman said: “The climate projections show that the oceanic vapor flux will only increase over time, providing even more fresh water supply.

“So, the idea we are proposing will be feasible under climate change. This provides a much needed and effective approach for adaptation to climate change, particularly to vulnerable populations living in arid and semi-arid regions of the world.”

The researchers said one of the more "elegant" features of the proposed solution is that it works like the natural water cycle.

Dominguez added: “The difference is that we can guide where the evaporated water from the ocean goes..

“When Praveen approached me with this idea, we both wondered why nobody had thought about it before because it seemed like such an obvious solution.

But it hasn’t been done before, and I think it is because researchers are so focused on land-based solutions – but our study shows other options do, in fact, exist.”

The researchers said their study, published in the journal Scientific Reports, opens the door for new infrastructure investments that can effectively address the increasing global scarcity of fresh water.