Canals make me think of traveling through life on a fixed way. They have chosen this way because it is an easy path, reliable, only one way to go, others are using it and there are places to stop and rest, you can also once you have stopped venture a little way off to try something different, but you always have to come back to the same route because you are tired to it.
The bible says that there is right and wrong paths to follow and the right path is narrow and when you move off of it you can fall and stumble because you get lead astray.
Hosea 14 9
Let those who are wise understand these things.
Let those with discernment listen carefully.
The paths of the Lord are true and right,
and righteous people live by walking in them.
But in those paths sinners stumble and fall.