It just crawled out of the canal bed. That is why it is covered in green slime. This one was a medium size. Their claws can be quite powerful! https://en.wikipedia.org/wiki/Common_snapping_turtle
They are such prehistoric looking creatures and I always love to see them. Here, they are now considered a species at risk because of habitat loss and roadkills (yet they are still legally hunted!). Beautiful shot. Love the green duckweed on her. V