I'm trying to cook up an interesting desert planet. Dune made me wonder if a tool-using species could turn a planet with plenty of water into a desert planet. Say, one nation starts hoarding water via the "catchments" we saw on Arakis (with some plausible mechanism to prevent evaporation), which kicks off a sort of arms race where everybody's doing it so they don't get left behind. And before they know it, they've sequestered all the liquid water on the planet underground. No more precipitation, no more oceans, seas, or lakes. But I'm not attached to my explanation. I just want a desert planet, but one with enough water to sustain enough agriculture to support a certain level of civilization, and a population big enough for the planet to be interesting. Something like Tatooine, with its "moisture farmers" and "vaporators" would be okay, too. Another explanation could be an Earth-like planet, but with one ginormous, roughly-circular continent. The coasts and near-coastal inland regions would be okay, but the interior would be a vast desert. Or, it could be the liquid water is all trapped far below the surface, but giant cactus-like species evolved to tap into it. And then higher life evolved by exploiting these cactii-wells. Or colonized the planet by exploiting them. I'm just looking for some ideas here. TIA.