The raised structure -- accessible via collapsible stairs -- was roofed with corrugated plastic panels and protected from flood-time driftwood by tension wires at the gable ends. The expansive roof was designed to shield the walls from heavy rains, and was surrounded by a deck which could be used as a fishing perch.
See some of Leen's photographs at GettyImages.
*Available in the Southeastern Architectural Archive, Special Collections Division, Tulane University Libraries.