Everglades Navigation Tip

I recently came across this video containing a very local navigation tip, for the Florida Everglades.

http://www.youtube.com/watch?v=atJAKWAeYHM

The fact that the water flows from north to south could be picked up in a number of ways from the environment itself, but here an improvised instrument does a good job.

Although it is possible that we will never visit the Everglades or need this exact piece of knowledge, each one of these ideas is still valuable. Each local insight encourages us to look for  trends in our own environment, however many thousands of miles away that might be.