Just as I was walking on the University of the Sunshine Coast campus today I noticed a little feature for Rain Water Management from the roof of the the Sunshine Coast Innovation Centre. The Sunshine Coast is subject to severe weather systems and a lot of rain during the summer (Rain Season).
What I want you to notice is the use of chains to lead the water from the roof to the sewer. The roof of the building is fairly large, and the amount of rain would be extremely significant in case of a rain storm. This will create a massive pressure on the gutter and without the chains the water would be as a waterfall from the roof.
A great little design feature of Tropical Australian architecture.