Water Witch is a science fiction novel by authors Connie Willis and Cynthia Felice that was first published in 1982.
Plot introduction
On the desert planet of Mahali, political power is held by a hereditary line of water witches who can sense and control water. A young con artist girl named Deza tries to impersonate a water witch, helped by the spirit of her recently dead conman father, who now resides in a small animal called a mbuzi.