Scientists analyze San Diego fog

Fog collectors will dry out our chaparral

— Get this: Johnny Cloud is into fog. Joel Blanket is into fog. Jerry Estberg (read "East Mountain") is into fog. Fog Cloud, Fog Blanket, Fog Mountain... Is this destiny or what?

The three scientists are united by one thought: All that fog we've been seeing waft across San Diego Bay this winter, disrupting air traffic at Lindbergh, causing crashes on the freeways, isn't a nuisance, it's a resource. We should be drinking it.

Fog, they say, is like a free desalination plant. It lifts water out of the ocean, extracts the salt, then brings all that freshwater vapor to us at head level, just begging to be drunk. A reliable water supply! Untapped!

But how to extract it? The answer is so simple, so low-tech it's almost silly. Fog blankets. Usually 100 square feet, made of porous plastic mesh, strung between poles, facing the oncoming fog. A drip tray below. Storage tanks capable of collecting, typically, 27 gallons of the purest drinking water every day. And that's just from one blanket, collecting fog droplets so small that it takes 10 billion of them to form one droplet of water.

"The reason I got onto this whole thing," says Jerry Estberg, a professor of physics at USD, "is I noticed as you drove up to Alpine [at a certain altitude] there was an increase in the size of the chaparral. I began to wonder why that was. Turned out it has to do with cloud layer. Above Alpine, above the cloud layer, it's quite dry."

A few visits later, Estberg realized that what was helping that level of chaparral -- everywhere in San Diego's foothills, from Iron Mountain to Mount Soledad -- was nothing less than low fog coming in, bumping against the hills and releasing its liquid.

"It turns out you get the maximum deposition right at what's called the 'inversion layer,' " he says. "The temperature, rather than dropping, goes up at a certain level, typically at 1500 feet. So I would go up above Poway -- there's kind of a shelf up there -- on the way to Ramona. It's just below Iron Mountain. There were several places: I also took data on Mount Soledad. This is a very cheap thing to implement. You basically put a screen up and set a trough below it to catch the water that drips off the screen. That's how I got started with the whole thing."

Entire ecosystems, like the Torrey Pine forest in Del Mar, he realized, depended for their survival on water they extracted from fog.

Graduate student John Cloud had the same epiphany.

"I am brand new getting into fog," he says, speaking from Santa Barbara, where he's experimenting with finding moisture to save native flora. "I'd had a wild idea: if I could capture summer moisture, it would help with the survival of my willows."

He got turned on to fog the first day he threw a fog blanket over a barbed-wire fence.

"There was a seemingly dry fog; there wasn't any precipitation or any wetness to the ground. But when I went back up to the barbed-wire fence, the mesh was soaked. It works very well in pulling the water out of the air. I'm doing it for ecological purposes, but I realized it has big possibilities for people, particularly under circumstances where access to good water is limited."

That's exactly what struck Joel Hernandez Blanket, a master's graduate in hydraulics from the University of Baja California. Blanket, from Ensenada, has launched a campaign to milk the fog for people living at some of Baja's most desiccated settlements. He has already built his first ten collectors at Punta Baja (also known as Fish Camp), a poor community of 60 people on the coast near the town of El Rosario, 250 miles south of San Diego. There, the fog rolls in over the headland pretty much year-round.

"I began [construction] last September, and I'll finish this September. It will be 30 collectors of 100 square feet each, 3000 square feet. They'll extract 3000 liters of water per day from the fog -- say 800 gallons -- enough for 90 people. And Punta Baja only has 60 residents. That's over 30 liters or nearly 10 gallons each per day."

Blanket says the fog blankets will supply all water needs for "at least half of the year."


Blanket, Cloud, and Estberg owe much of what they have learned to the guru of the fog movement, Robert Schemenauer, a 51-year-old "cloud scientist" from Toronto. Estberg says Schemenauer is known as the "international gadfly of fog water collection."

It was Schemenauer who noticed how many hot, dry coastal lands coexisted with cold-water currents and had little or no rainfall yet lots of fog. Schemenauer has traveled the world seeking out sites, from Yemen to Ecuador to South Africa to the mountains of Nepal. Above all, the dry sands of Chile's Atacama coastal desert communities gave him an opportunity to try out his theories. One name has made him famous: Chungungo, a dying Chilean Atacama village of 330 he saved with 88 fog blankets.

"We started working there in 1987," he says. "The population was going down. There wasn't too much hope for a better future. People [were] moving away to live in [the slums of] big cities, hoping for work.

"We erected 88 large fog collectors. They worked! They produced an average of about 3000 gallons a day. On very good days they'll produce 25,000 gallons or more. The water is supplied year-round, though there's a seasonality to it. Their [Southern Hemisphere] springtime months, October, November, December, are the best. In summer and winter the elevation of the cloud changes. We [have set up the fog collector blankets] at a range of altitudes that is chosen to allow us to collect a lot of water at the best times of the year and moderate amounts of water at the poorer times."

Schemenauer says the effect on the community has been dramatic.

"They've had the running fog water since March of 1992. Coming up seven years. There are about 120 houses. Each house has a tap with running fog water. The school has fog water, and what businesses there are have running fog water. They wash their clothes in it...but they use it carefully. Once they've cooked in it, they'll pour it on the plants outside."

And with water, he says, Chungungo is a much more pleasant place to live.

"Now the population is going back up, from 330 to 400. During the summer season, it's over 500 people. [They used to depend on] poor-quality water delivered irregularly from a truck. Now you have good-quality water available all the time. You can have gardens now. They have vegetables and fruit trees. A year after we got the water flowing, the municipality decided to put a power line for electricity in. Before, they depended on a generator. Two years ago they got a gas pump, and people who used to live there now come back and spend their summers."

Baja California, Schemenauer says, has the same "ideal" conditions to bring in fog technology.

"First it has the social need, and that's one of the things we look for. It is an arid place where there is a need for water. And there are lots of small places -- towns, individual settlements, farms, ranches, homes -- that need fresh water. Secondly, it has reasonable elevations, both near the coastline and inland, and it has a cold ocean current offshore coming down from the north. That's one of the important components in producing low layers of cloud offshore. And when you have westerly winds blowing inland, they will push that low layer of cloud over the terrain, and where the terrain intersects with that cloud, there you have a place where you can [put up fog blankets and] take that water out."

And Southern California? Prosperity will probably kill fog-to-water schemes before they're born, Schemenauer believes. "You're too rich. Wealthy countries can afford established technologies. A town of 400 in California will have a pipeline already. It won't need fog because it can afford to buy water. A poor town of 2500 in Peru or Chile may never get a pipeline."

Pollution, he says, is not a problem, even though he recognizes that "acid fog" is "very much" a reality in California.

"But really, acidic events are very rare, and even if you have quite acidic fog, like acid rain, damaging forests if you have it long enough, you can still take that water, put it in a glass, and drink it, and it'll be just fine. You can drink it for all of your life. It's not as acidic as orange juice, not as acidic as vinegar by any means, not as acidic as wine. If you looked at the concentrations of all the major irons and heavy metals in that fog water, it would probably still meet the World Health Organization drinking-water standards. So even if you collected acidic fog in downtown Los Angeles, there's a fair chance you would meet the standards."

But Estberg thinks the whole idea won't work here. "It's an intriguing concept. But in terms of San Diego, practically, I don't think you're going to be able to say that it will save us from our [water] problems. Possibly up toward Iron Mountain you could get some deposition at some times of the year, but it's not a major resource. It certainly would not be something anybody would look at in terms of water supply in San Diego. Also, it turns out that as you go from Point Conception south for a ways, the ocean is warmer, and there's just not enough fog to make it worth it. Down toward [Punta Baja], I think the relative water temperatures are lower there, and they [start to] get a fair amount of fog deposition again. Fog is not enough of a resource to be feasible for San Diego."

Besides, says Estberg, "every bit of fog you collect is going to rob water from the chaparral. Everything downwind from these vertical collectors is [going to suffer]."

Schemenauer doesn't agree. "Think of the layer of cloud flowing over the hills as being 200 meters thick. We work in the lower six meters only, and we have spaces between our collectors, and even the fog that goes through the collectors, we only collect 50 percent of it. [In Chile the fog rolls inland] for 1000 kilometers of coastline. We work in [just] one kilometer of it. We collect just a tiny amount, but it's a very valuable amount for the community."

John Cloud feels fog collectors could be used for getting the maximum out of rain clouds too. "With fog collectors, you can wring more water out of a rainstorm. Normally what we get as rain is just precipitate, and those are relatively huge drops of water, as opposed to the size of fog droplets. But the same rain cloud can have lots of smaller droplets associated with it. So if you can collect those, you can augment the moisture you get from the rainfall alone."

Joel Blanket has no doubts about fog's future in Baja. Punta Baja, he says, is the perfect candidate for this sort of technology.

"Communities, poor communities of less than 100, are the ideal size for this. The beauty is that summer, when it's hottest and driest, is when you get the best fogs. And Punta Baja is just a beginning."

Of course, he needs money. The Agencia Española de Cooperación Internacional gave him $30,000 for the Punta Baja job. He has applied to the federal and state authorities of the Mexican government for grants to continue to project in Cedros Island and Guerrero Negro (near Scammon's Lagoon) but so far has had no replies.

In fact, asked where he's going to find the cash, he says right now he hasn't the foggiest.

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