[bulrush]

Thanks everyone. Shortly after I posted this I did a search and found a water snake that looked just like this. Several years ago I did look for photos of water snakes, and found pics of the norther water snake that had a VERY arrow-shaped head, like a rattler, it was black with mostly even dark gray triangles. I saw snakes matching those photos in a park.

But, I believe you, it must be a northern water snake. These guys move MUCH fastser on land than a garter. As soon as we spot them, BOOM!, they are gone.

This one was apparently sleeping on a bush, so we ran home, got a net, returned and he was still asleep. I tried to catch him in the net but he escaped. He fell in the water and we never saw him again.