And here's another one farther North of the Yellow Sea in a less advanced state of development. I am guessing deserts should be easier in light of not having to deal with all the salt water and ghosts of samurai pirates. You just gradually redirect and capture local waterways adjacent to the barren lands and gradually build a sustainable ecosystem. Ancient Egyptians could manage it I don't see why the zipper heads shouldn't be able to as well aided by modern earth working tech.