"Shade balls" kind of sounds like the slang the kids would use these days, as in "When that girl talked shit about my outfit, I was casting shade balls at her at night."
But, no! This is a thing where plastic balls absorb the sunlight instead of the water in a reservoir which should reduce evaporation. It also should cut down on bacteria growth in the water (some aquaculturists working in gardens with koi ponds add a kind of ink to reduce algae blooms, so I get that principle) and nothing from the plastic itself should leak into the water. At first I wasn't 100% on how this would work because it seemed to me that if dark-colored balls absorbed solar heat, that heat would redistribute along the surface area of each ball transferring it to the water causing more of an evaporation effect. But smarter people than me apparently worked out that the surface absorbs the heat, but the water-side is protected. If this works how the smart folks say, call me impressed!
I'm not terribly impressed by some arguments of some people, which seem to hinge on the idea that California should have built more reservoirs to catch the water that the state is currently not getting. I prefer to believe that if people accept that climate change is real, they can deal with it using real solutions, instead of bitching about what might have been without actually presenting any solutions at all. I really don't see professional blame-redistributors as innovative in that necessary sense.