For one thing I've become aware of is how long the subtle impressions of boats travelling along the river can last. For example the photo above was taken a few minutes after a slow moving tourist boat went by leaving behind these neat straight lines.
According to Wikipedia wakes are formed in deep water or when the speed of the boat is greater than the speed of waves, neither of which was probably the case here. So what we have are the bubbles left by collapsing waves and the slightly smoother water it left behind (I must find some more references for this behaviour).
So maybe those apparently random patterns in the rain could have been twisted imprints of boats that had passed by, like the memory of the river.
Rather an appropriate connection to a science fiction story about a self-aware ocean!
