There's some testing to see how covering open irrigation canals with solar panels which would reduce evaporation and generate power

> Their analysis found that putting solar panels over the 4,000 miles of California’s open canals could save up to 63 billion gallons of water annually

https://www.universityofcalifornia.edu/news/solar-panel-cove...

> could save up to 63 billion gallons of water annually

To put it into perspective, 63 billion gallons is 193340 acre-feet, which is 0.5% of california's water use (a bit under 40 millions acre-feet). That's a tenth the water consumption of lawns, which is 1/15th the water consumption of agriculture.

Thanks! I forgot that article, but now I remember that I read or skimmed it when it made the rounds last year. It's actually where I first learned that the aqueducts were uncovered!