The Los Angeles Reservoir, 175 acres of freshwater destined for the taps of our second-largest city, looks, to me, like an oil slick that has begun to freeze into some ghastly ice sheet. A closer look, though, reveals thousands of little plastic balls, bobbing about at the water line. They’re neither litter nor art installation, though Los Angeles is rich in both; they are, in fact, the most imaginative technique I’ve heard of for maintaining water quality and quantity in Southern California.
As you surely know, California has been enduring a horrifying, though not surprising, drought for the last several years—and while help may be on the way this winter, the situation remains pretty dire. There have been a lot of creative responses to the drought over the last few years, some of which I’ve written about here, here, and here, and which I assumed would be my last entryways to the topic for a while. But when, in mid-August, my Facebook feed drowned under a deluge of something called “shade balls,” I knew I had to revisit the Golden State and its water problems.
The people with the thankless task of watering four million Angelenos are employed by the LA Department of Water and Power. Urban water is a massive and intensely difficult issue—I often tell my students that if they get into urban water they will have jobs, and headaches, for life. Reservoirs in any city, but especially an arid one like Los Angeles, are subject to all manner of urban problems, from litter to the urban heat island effect. In 2005, the EPA released a rule upgrading the management of finished water reservoirs—reservoirs containing water that goes straight to the people without further treatment. New ones needed to come with a cover. Pre-existing reservoirs could either be covered or send their water to be treated, which is expensive. Some places have dealt with this by storing the water underground and building parks on top, but that idea, while good enough to mention here, is not feasible everywhere. How to cover an artificial lake?
The first thing you might think of would be a gigantic tarp, and it is, in fact, a popular idea. But to cover the LA Reservoir with some sort of floating tarp would cost hundreds of millions of dollars. A guy named Brian White, who worked for LADWP as a biologist, gets credit as the first to think of covering the water with floating objects, like an oversubscribed kiddie pool at a six-year-old’s birthday. He’d seen ponds at airports with balls to keep birds off the water (and out of 747 engines) and transferred the idea to LADWP’s reservoirs. As of mid-August, under the supervision of Mayor Eric Garcetti, the final 20,000 of 96 million balls rolled down the concrete and into the water. The total cost of the program is $34.5 million (36 cents a ball)—a pretty good deal compared to a new water treatment plant or a floating tarp system.
The balls have two functions. The most obvious one, of course, is shade. The balls will cover the water and prevent it from evaporating, saving an estimated 300 million gallons of water per year (LA consumes over a billion gallons a week, for a little perspective). Evaporation is one of the catch-22s of our Western water infrastructure—to have a desert civilization you must store water, but if you do, the same desert conditions that make water storage necessary will suck that water right up into the air. For instance, Lake Mead, the immense reservoir held back by the Hoover Dam, loses 800,000 acre-feet of water, or 2.6 trillion gallons, to evaporation every year. Shade balls present a nice, cheapish way to alleviate the problem.
The balls’ more important function, though, is to maintain water quality. As water gets warmer, algae blooms, and chemical reactions create pollution where there was none before. The central concern is bromate, which may cause cancer. Bromate is created when ozone, which is used for water purification, combines with bromide, which occurs naturally in water. UV light kickstarts the reaction (photoactivation is the term), and the result is a plague for water managers everywhere. Eight years ago, LADWP had to drain two of its reservoirs because of bromate pollution. The shade balls’ pigment, a substance called carbon black, maximizes their ability to absorb UV light, keeping it, and bromate, out of LA’s water.
I have to be honest. At first glance I figured that this was a really stupid idea and was expecting to say so here. And of course, it’s not ideal to produce millions of plastic balls—it would be better, say, to use less water. But other than this broad objection, there seem to be very few downsides to the approach. The balls, which I was sure would quickly bounce away and become trash, contain a little potable water themselves as ballast and cannot really go anywhere. Carbon black prevents them from breaking down under UV light, allowing them to last for decades. It’s a food-safe pigment, and is used as a food coloring in Australia and New Zealand. The balls are even made by a local company, called XavierC, which was founded in part to hire disabled veterans. The only downside, for some, is that Angelenos who are too creepy, sketchy, or shady in their pursuit of romantic attachments, are now known, in local parlance, as “shade balls.”
Peter Brewitt has wondered about infrastructure ever since a flood kept him away from three days of kindergarten. A professor of environmental studies at Wofford College, he is devoted to understanding how people decide to restore and remake their environments.