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Arizona's solar-over-canal project will tackle its major drought issue
(interestingengineering.com)
This is a most excellent place for technology news and articles.
It's also a win win design. Shade from the panels reduces evaporation in the canals and the water helps cool the panels which improves their efficiency.
It would be cheaper and easier to maintain separate instaaleions of a lightweight cover for the aquaduct and solar panel installed on solid ground. You could use the same money to add square miles of panels.