Not all of Ingham is flood-prone. There are parts at both ends of Lannercost St which aren't as subject to flooding as the main shopping centre strip. I know one such site which had duplexes built - the ground had to be raised above flood level (also backs onto the creek). Both have rented quite easily.
Plenty of people travel to Townsville for work or to the local mills at (Lucinda/Halifax).