Part of it's way stream does inside underground tubes. Several years ago it washed out some of these tubes and ruined a bridge above. Sections of these tubes still lie in the riverbed. One of that sections looked quite photogenic to me.
My small tripod helped me very much. Usually it is not very convenient because you always need to find something on which the tripod can be set up. But in this case camera had to be placed right above water level and it's legs moved apart widely (they can be placed nearly horizontal) ideally stood at stream banks. Some running with a flash to make light beams coming through a breach in a tube and a photo was done.