Coppers look nothing like Cottons.
If the onlookers were screaming Cotton, it was a water snake.
:)
My dad was a snake-o-phobe without equal.
He stocked the pond above me with bluegills, sunnies and catfish, and naturally, the water snakes came to feast.
One day, after a heavy rain, the pond overflowed into the dry run beside my lane and a water snake was displaced by the overflow.
I knew dad would be down from the ridge at any moment, so I spent 15 minutes, nonchalantly escorting the snake [and encouraging haste] down the stream until it reach the confluence at the end of the lane and made it to the culvert which went to the lake across the road.
A minute later, dad drove up and asked why I was standing in the road, for no apparent reason.
:)
My father was so petrified of snakes that he joined the Navy in WWII to preclude the possibility of being drafted into the army and having to crawl through snake-infested (as he imagined them) fields.
Until the day he died, if there was a snake shown on a TV show, he couldn't change the channel fast enough.
I'm pretty much the same; I consider you to be very, very brave.
I found this site with some good pictures; I recall the snake swimming below the water surface which would fit the water snake description: