“Desalination in California is helping reduce pressure on the Colorado River. By adding new supply, notably from the Carlsbad Desalination Plant in San Diego, coastal utilities are freeing up river water for other states in exchange for desalination funding,” reports The Doomslayer.
With the Colorado River in crisis, Arizona and Nevada are turning to an unconventional lifeline: the ocean water off California’s golden beaches.
Both desert states are pursuing a deal with the San Diego County Water Authority to tap millions of gallons of fresh water produced by a Carlsbad ocean-desalination plant—the largest in North America—to help offset their reliance on the collapsing Colorado River…
No water is literally shipped; rather, the parties would trade access rights to water sources. States would fund much of the estimated 56,000 acre-feet of water that the desalination plant produces annually in exchange for San Diego’s share of the Colorado River. The agreement could supply enough water for some 500,000 people…
San Diego became a water broker by necessity. During a five-year drought that ended in 1992, the San Diego County Water Authority lost a third of its allocation, which came almost entirely from imported shipments…
Over the next three decades, the authority invested billions to achieve water independence. It raised the height of a dam to double its storage, built the desalination plant and acquired rights to a trove of conserved Colorado River water from a desert farming district. In doing so, San Diego slashed its water imports from 95% to 10%.
Many counties with low rainfall are now turning seawater into drinking water using big desalination plants, such as Malta, Israel, and the United Arab Emirates. In addition, there are now floating desalination machines that use no electricity, which are “100% mechanically driven”: “Oneka’s floating desalination machines – buoys anchored to the seabed – use a membrane system that is solely powered by the movement of the waves. The buoys absorb energy from passing waves, and covert it into mechanical pumping forces that draw in seawater and push around a quarter of it through the desalination system. The fresh, drinking water is then pumped to land through pipelines, again only using the power provided by the waves.”
Drinking water could also be collected from thin air, especially in places like the island nation of Bahrain that are humid, yet seldom receive rain (Peru’s capital, Lima, also is humid, yet receives little rain):
Cody Friesen, an associate professor of materials science at Arizona State University, has developed a solar-powered hydropanel that can absorb water vapor at high volumes when exposed to sunlight. It is a modern-day twist on an approach been used for centuries to pull water from the atmosphere, such as using trees or nets to “catch” fog in Peru, a practice that dates back to the 1500s and is still being used today….Friesen founded his own company Zero Mass Water in 2014 following his research on solar-powered hydropanels. Today the company is called Source Global, operates in more than 50 countries and has a private valuation of more than $1bn (£800m).
The panels work by using sunlight to power fans that pull air into the device, which contains a desiccant material which absorbs and traps moisture. The water molecules accumulate and are emitted as water vapor as the solar energy raises the temperature of the panel to create a high-humidity gas. This then condenses into a liquid before minerals are added to make it drinkable.
“That’s how we’re able to create water in most places in the world, even when it’s very dry,” says Friesen. “We’re headquartered in Scottsdale, Arizona, which is sub-5% relative humidity in the summer and we’re still making water. It’s a uniquely efficient and low-cost approach that enables us to go places where nobody else can go.”
The air, even in relatively dry climates, can hold a surprising amount of water. The Earth’s atmosphere as a whole contains about six times as much water as the planet’s rivers.
