16 Aug 2015

Meta-tweet on LA's balls and water scarcity

NB: I had to write this post in response to a twitter "conversation" that was too tangled to resolve in 140 character chunks. I'm guessing this won't be the first time. Life is complex.

Last week the Guardian showed photos from an Los Angeles Department of Water and Power (LADWP) media event (lots of cameras in the pix) where LADWP claimed they were using 96 million black plastic balls on its Sylmar Reservoir to "stop 300m gallons of water evaporating each year." I did some quick calculations (36 cents each, 10 year life span) and tweeted:
Several people (including LADWP) replied to my tweet with observations that (1) the balls were more about UV protection to keep (treated) water from biodegrading into undrinkable water and that (2) the balls were cheaper than a $300 million rubber tarp and (3) longer lasting than 10 years (25 in fact).
  1. I knew 6 years ago that the balls were NOT about reducing evaporation. 
  2. $300 million is also a lot, but what about revenue neutral or saving ideas like LADWP ending its "more cheap water for lawns in summer" policy (or worse)?
  3. $3.7k/af goes to $1,500/af, which is still a lot of money
All I was responding to was the article's spin (LADWP's spin?) that it was using balls to save water (check out all these articles!). I would have said nothing if the story had said "LADWP is required to spend this money on balls. The good news is that it also saves some water," but that's not what they said (this story is better), and I was tweeting to deflate their "we're conserving water" spin.

Indeed, if you think the balls are ONLY about evaporation, then you will see them on non-treated water reservoirs, but... no sign of that.

Bottom Line: Water managers need to be clearer about why and when they are spending ratepayer money. Even better, they should implement both demand reducing and supply augmenting policies in times of water scarcity (or all the time).

H/Ts to SC, DP, LS and DV


Damian Park said...

The other interesting thing is the usefulness of EPA s coverage mandate. Is this a good technological mandate or just another costly reg

Anonymous said...

Turns out they are not to control evaporation, per Quora:

QUOTE: I went to the LAPDW website and found that the main reason for these balls is to minimize the risk of bromate-forming chemical reactions due to sunlight striking the water. Basically, it is a nice side effect that they also reduce evaporation.

There is a point of contact for that project, so I him an e-mail and asked this question. Here's what he said:

The shade balls used by LADWP are high density polyethylene and are approved for contact with drinking water by the National Science Foundation. They use the same material as one gallon milk containers. The carbon black is an added layer of UV protection from the sun. To have used other colors would have required dyes, which do leech into the water. The carbon black does not emit or leech any chemicals.

So any other color would fall apart quicker and would leech chemicals into the water. Only the black ones don’t./QUOTE

Nice to know that officials do not know the difference between “leech” and “leach”.

Post a Comment

Note: only a member of this blog may post a comment.