I remember that “canal water” reference from the veetnam days. Our Brown Water Navy operated in those muddy coastal rivers and irrigation canals. There was lots of weird stuff living/floating in those waters-—
I worked with 1 guy for a very long time. He did two Nam Tours at least. He was one of those guys who joined the Air Force and the Army.
One day he brought in his medals and other memorabilia from his active duty days. I was very impressed. I served, but there was no ongoing conflict during my time.
He used to say that Canal Water stuff all the time. It made me laugh, but it had no meaning to me. Once I heard it said from others, I knew that there was something to it.
Incidentally, I, my son, my father, my grand father, and great grandfather all served in the U.S. Army. Each of them served during active hostilities. Only myself never saw any battlefield.