Desalination Is Booming as Cities Run out of Water

This story originally appeared on Yale Environment 360 and is part of the Climate Desk collaboration. Some 30 miles north of San Diego, along the Pacific Coast, sits the Claude “Bud” Lewis Carlsbad Desalination Plant, the largest effort to turn salt water into fresh water in North America. Each day 100 million gallons of seawater are pushed through semi-permeable membranes to create 50 million gallons of water that is piped to municipal users. Carlsbad, which became fully operational in 2015, creates about 10 percent of the fresh water the 3.1 million people in the region use, at about twice the cost of the other main source of water. Expensive, yes, but vital for the fact that it is local and …

Why Are 96,000,000 Black Balls On This Reservoir?

Veritasium took a boat through 96 million black plastic balls on the Los Angeles reservoir to find out why they’re there. The first time he heard about shade balls the claim was they reduce evaporation. But it turns out this isn’t the reason they were introduced. The balls are made of high density polyethylene (HDPE) which is less dense than water so they float on the surface of the reservoir even if they break apart. They are 10cm (4 inches) in diameter and contain about 210ml of water. So the main reason they are on the reservoir is to block sunlight from entering the water and triggering a chemical reaction that turns harmless bromide into carcinogenic bromate. This effect occurs …