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California Fights Drought With 96 Million "Shade Balls"
HughPickens.com writes: Katie Rogers writes in the NY Times that the city of Los Angeles is releasing 96 million plastic "shade balls" into the 175-acre Los Angeles Reservoir to help block sunlight and UV rays that promote algae growth, which would help keep the city's drinking water safe. Officials also say the balls will help slow the rate of evaporation, which drains the water supply of about 300 million gallons a year. The balls cost $0.36 each and are part of a $34.5 million initiative to protect the water supply. Shade balls are the brainchild of Brian White, a biologist with the utility who based the idea on "bird balls" that he observed in waterways near airport runways to prevent airfield bird strikes. The Los Angeles Reservoir, which holds 3.3 billion gallons, or enough water to supply the city for up to three weeks, joins three other reservoirs already covered in the shade balls. "In the midst of California's historic drought, it takes bold ingenuity to maximize my goals for water conservation," says Mayor Eric Garcetti who was at the Los Angeles Reservoir to mark the addition of 20,000 of the small balls to the lake. "This effort by LADWP is emblematic of the kind of the creative thinking we need to meet those challenges."
To the extent the point was to keep heat away from the water, I wonder why they didn't go for something with a high albedo instead of black.
So if the surface is completely covered with these black ping pong ball like things, doesn't that also reduce oxygen exchange?
Is there a risk that they just turn the lake into an anoxic wasteland (sulfides are quite toxic) if they do this ?
"In the midst of California's historic drought, it takes bold ingenuity to maximize my goals for water conservation," says Mayor Eric Garcetti
Or you could, you know, tell all those rich idiots who insist on acre-sized green lawns in the middle of the desert "tough luck".
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They reportedly considered a floating shade cloth, but found this to be a cheaper solution when all costs were factored in.
Why is it cheaper? Don't ask me. But it reportedly is.
IMHO, the "ideal" solution would probably be to use the area over the water for productive purposes, such as floating sealed algae farm or floating solar farm, so that you're both stopping evaporation and getting a secondary benefit with the same system. But the overhead times and costs would obviously be much higher for that.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
Make that 2008: http://www.popsci.com/holly-ot...
Of course news about a fake are Fake News.
but I'd rather see more desalinization plants. The trouble is shade balls were probably pretty cheap. If you think California lacks the political will to tell their 1% to back off on the water usage try getting the tax raises through needed to support desalinization plants.
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Because the company that makes them is owned by a close friend of the guy who decided to use them? ;-)
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My guess would be that these are easy to transport and deploy. Pulling a cloth over means getting a boat and keeping it lined up. Also needs to be transported in one piece. Balls can be loaded into a dump truck, driven to any point around the reservoir, and just dumped in. They'll spread out by themselves.
And plastic balls are very cheap. These don't even need to be particularly good quality. Stamp them in a mould, glue two halves together, you're done.
Yeah, let's just fling any old kind of plastic on top of our water supply without checking that it won't rot in the sun and leach whatever chemical its made of into the water, or melt into a sheet that starves the water of oxygen, or chokes the local wildlife. Oh, and you'll have to get them painted black first.
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Those who do not pay attention to the world around them, are doomed to reinvent the wheel (or in this case, balls covering water).
Thirty years ago, I was living in Sweden, where it was already nothing new that you cover an outdoor swimming pool with ping-pong balls to prevent heat losses and related evaporation. How come this was news, and a great stroke of genius, in California?
As an aside, they don't interfere with the use of the pool at all. You can dive in through them.
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They are creating an environment for an algae bloom that are starting to cause problems everywhere.
The algea blooms, which are not truly algae but are cyanobacteria, use less light(lower wave length) want low oxygen environments with lower water turbulence. And they are creating that.
Once cyanobacteria bloom starts, it's very difficult and costly to control. It' has very few natural predictors, I don't know of any freshwater ones, and worse yet, cyanobacteria can create toxins that have killed dogs running through it.
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For the 1989 Movie The Abyss James Cameron shot the underwater sequences for the film were shot at an unfinished Cherokee Nuclear Power Plant, situated outside Gaffney, South Carolina, which had been abandoned by Duke Power. Two specially constructed tanks were used. The first one held 7.5 million US gallons (28,000 m3) of water, was 55 feet (18 m) deep and 209 feet (70 m) across. At the time, it was the largest fresh-water filtered tank in the world. Additional scenes were shot in the second tank, which held 2.5 million US gallons (9,500 m3) of water. The filmmakers had to figure out how to keep the water clear enough to shoot and dark enough to look realistic at 2,000 feet (700 m), which was achieved by floating a thick layer of plastic beads in the water and covering the top of the tank with an enormous tarpaulin.
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You have to love how they use gallons as a unit of measurement because it gives a really big number - 300,000,000. But in water terms, that's actually very little. That computes out to just under 921 acre-feet, which is the standard unit of measuring large quantities of water. Not so impressive-sounding now, so let's see what the actual costs are. Divide the $34,500,000 cost by the number of acre-feet and then again by the expected lifetime of the balls - say, 20 years. You wind up with $1,900 per acre-foot. This is a lot of money, but California residents and normal businesses normally pay around $1,000 per acre-foot. If you amortize the cost of these balls over the total water going through the system it's still a bit pricey but not insane when you consider the effects of droughts. For example, in Carlsbad, California they are building a desalinization plant with guaranteed annual sales at a cost of just over $2,000 per acre-foot.
Of course, real sanity would address the real causes of the "drought" - the fact that the two groups that use 85% of California's water pay nowhere near this much. Government pays $0 per acre-foot and wastes a breathtaking amount of water. Big agriculture pays around $10 per acre-foot (the small organic farms I buy my produce from still pay the two-orders-of-magnitude-higher residential rates). I'm all for agriculture - California is an amazing place to grow food and provides a huge percentage of the fruits and vegetables consumed in the US - but the artificially low prices have been abused by some farms and orchards. There is still a lot of flood irrigation being used (and some farmers were actually growing rice in the desert). A massive amount of alfalfa is being grown in the desert and then shipped to China, because at the subsidized water prices this is actually cheaper than China growing their own hay. Sit back and bask in that insanity. The government has dumped as much as a third of California's water supply for various environmental purposes - you could argue the costs and merits of this except for the fact that none of these projects are having their desired effect, so all of that water is just pure waste (around 33% of state water usage). And then they threaten to fine us if we water our lawns more than twice a week (> 5% of state water usage).
So anyway, for once, the black balls are the government doing something expensive but not completely stupid. But the fact that this is even necessary due to government stupidity and a breathtakingly colossal mismanagement of a valuable natural resource sort of makes it all moot in the end. There is no shortage due to drought - there's a shortage due to bad policies.
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Why is it cheaper? Don't ask me. But it reportedly is.
The balls require no maintenance, aside from replacing lost or stolen balls. Nothing is really going to be damaging them out there besides the elements, which will work on them only slowly due to their nature. A cloth would just be an algae-growing substrate mat.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Why not use a thin layer of biodegradable oil as has been proposed to weaken hurricanes? That would prevent evaporation and cost a lot less, I'd imagine. I doubt the oil would cause problems since the water is likely drained from below the surface. The only downside is the possible damage to wildlife.
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Water is already a near-ideal absorber of sunlight, so the black balls shouldn't change much in that respect, except to keep much more of the heat on the surface. They are also quite likely much better heat radiators, which should be even more helpful since the heat will be more concentrated (hotter) and thus radiate far more rapidly.
I also don't know that wind would be a problem - it sounds like they're trying to pack these pretty tightly, so it's not like they're going to be able to freely roll around the surface and lift a film of fast-evaporating water. It'll take a heck of a wind to rotate them against each other, especially considering they're almost completely shielded from the force by their upwind fellows. So most of the time I would suspect they would remain relatively stationary, with their top surfaces getting very hot, and their plastic construction largely failing to conduct that heat down to the water's surface.
I do agree that white balls (preferably a beyond-visual solar white) would seem to be a considerably better solution at first glance, but I can think of several possible confounding factors:
- Longevity: As a rule plastic breaks down rapidly in direct sunlight. These are probably carbon-black, which I suspect is is about as good as it gets for both cost, UV protection, and non-toxicity. Alternate UV-protective dyes are likely to be more expensive, less effective, and more toxic. Plus the faster degradation would increase clean-up and replacement costs as the balls degrade.
- Costs: these balls are already mass-produced for other reservoir-related purposes: a new design would add at least some design and retooling costs
- Testing (money and time): these balls have already been used in reservoirs and thus (hopefully) the health and safety issues have received at least some study. Reformulate the balls and you'll need to do those studies again.
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You say that like the point is to save money rather than water. You can't drink money. Crops don't do too well on it either. And California is rapidly losing their traditional imported water sources since surrounding states are mostly faced with the same drought and are increasingly unwilling to sell their own water.
So, the options are:
Conserve water
Buy more water at prices sufficiently elevated to tempt surrounding states to sacrifice their own dwindling water supplies
Start building desalination plants (generally $2-$3/1000 gallons, or about $650-$1000 per acre-foot)
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Rich people watering lawns is not the problem. Residential water use, ALL residential water use in California, accounts for about 4% of our annual use. It is unrestricted use by big agricultural concerns that use OVER 80% of our water. They still flood fields for christ's sake!!! Their is no incentive for them to use modern water wise farming practices since they have "senior rights" going back centuries. We can't even pass a law restricting them so now we grow rice in flooded fields. Just stupid.
In other news, thousands of Golden Retrievers have been observed hitch-hiking to Los Angeles to participate in an event described by one traveller as, "a canine Burning Man festival". "It's like somes guy just kept throwing balls and throwing balls, but der was no dog to go get 'em," said Max, a 7-year-old neutor from Chicago.
The overlap between balls probably means you're only covering about 80-90% of the surface at best.
Those numbers would be if the sun is overhead all the time, but it's at an angle the vast majority of the time and the balls do have height.
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I'm not sure exactly what material weight you would need if using a tarp, but using premium quality 10oz vinyl baseball fields tarp (170 feet by 170 feet at a weight of 2300 lbs) as a basis for calculation, you would need more than 300 tons of tarp to cover the 175 acre reservoir, which you would have to ship to the site, deploy over the water, and anchor down somehow. The anchoring would have to handle all weather and wind conditions, and since its on water, you can't just put weights on top, so either you have to install posts throughout the reservoir to attach the tarps (not cheap), or you have to attach actual anchors to the tarps with depth ropes set correctly so as not to drag the tarps under. You could also tie the tarps together but that could also cause bigger problems if a big windstorm got a handle on it, like those videos of storms lifting and flipping the tarp at baseball stadiums during deployment. Tarps lead to other problems too. Lets say you have to go out and make repairs on one of the posts or tarps in the middle of the reservoir; now you have to remove an entire series of tarps to get a boat to the needed area, and then redeploy those when you're done. If someone happens to fall into the water, the tarp would pretty much be a deathtrap, just like when someone falls into a covered pool. If someone falls in with the balls, its no big deal. The balls might cost slightly more than 175 acres of tarp in material costs, but cost of deployment and maintenance will be much lower. To deploy balls, all you really have to do is put them in, and they will spread out for you. To remove them, you just have a boat or equipment near that can scoop the balls up, or suck them out while putting the water back into the reservoir.