That's fantasy. If you don't live in the West it's difficult to appreciate that there simply is no water. No amount of of "swales" or rock dams change the fact that water doesn't fall from the sky in sufficient amounts to create a "lush green forest". Also every drop of water that hits the ground has been accounted for long ago and is part of some water pact. If you create a dam upstream you are guaranteed to get a visit from the water rights holders.
Actually, most of these regions have rain. (The Atacama does not!) And you do not need lush green forests right away, prairie grasses are a good start. Well-applied rain retention measures do work.
I contributed some code to a FOSS project recently which is written in C. In my 10 lines of contributions, 3 were a complex conditional. I'd have loved to do what the article suggests, with some intermediate booleans. But that C version would have required me to define those variables at the beginning of the function, a hundred lines earlier instead of just right there. No way that's going to fly, so now they will need to live with a complex conditional. It's one of those "modern language" features which C fanatics generally frown upon but which makes code much easier to read.