Kinda like the system we have today?
I mean, I get your points, because having 10 reservoirs that are 10% filled is better than 5 reservoirs that are 10% filled. But at what cost?
Screw conserving water, let's just build more reservoirs to hold the water that we eventually misappropriate. That is certainly a solution....
Why not just build a few hundred desalination plants! Maybe a few thousand. That way we have water whenever we want it.