Following this thread reminds me that in the 1930s the Coast Guard constructed the Mother of All Water Reclamation Systems, which included a flat sloping concrete apron, roughly fifty yards by twenty yards. This collected the winter rains for the use of the newly erected lighthouse and quarters on Anacapa Island.

Unfortunately, it also collected the physical residue deposited by the thriving flock of sea gulls which inhabited and bred on the island, making the water distinctly gray. Eventually the system was abandoned and potable water was (and is) shipped to the island and stored in conventional tanks.

Today the catchment basin makes a really fine helicopter landing pad.