This little street shows how a portion of the storm drainage works in Cortona. On downhill streets, the section forms a “v” as shown here. (On cross hill streets, the section either forms a bow with gutters on both sides, or is canted to a gutter on the downhill side.)
The slope is about 3” in roughly 6’ on each side. Note the ridge where this street attaches to the one in the background – and the “v” section on that one as well. Note too how the paving pivots around the building edge. A 21″x12″ inlet is about where I was standing – it intercepts the water so it doesn’t build up too much mass or velocity.