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).OMG @LADWP! $34m for 900AF ($3.7k/af over 10 yrs)?!? http://t.co/r7djfWRoRR WASTE of $! Think diff! http://t.co/BSL3ALsHCm @WWLA @shelbygrad— David Zetland (@aguanomics) August 12, 2015
- I knew 6 years ago that the balls were NOT about reducing evaporation.
- $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)?
- $3.7k/af goes to $1,500/af, which is still a lot of money
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