Yeah, and building canals to make more "waterfront" properties.
Tampa bay and the ICW are spotted with them. They start as just area's on the chart marked as "Spoil Area" then eventually it goes from shallow, to shoal, to island, some palm trees grow on them (Swallows carry the seeds over, I'd imagine), people stop and party (I have a picture of my boat on that one of those very islands, it's a great picnic spot), then a storm comes through and redistributes it back across the ICW.
There's one in Tampa Bay that has done that whole lifecycle since I've lived here. Thos ICW ones are a little more protected, so once they stop dumping spoil, and trees get a foothold they last for a bit.