Last Friday, I was watching a couple of mallards swimming in the C&O Canal near Georgetown. Suddenly, a long, skinny object appeared in the water and started undulating rapidly towards the bank. I gazed at it in amazement for a few seconds before my brain circuitry announced that it was a snake. By the time I finished fumbling with my bag and managed to take my camera out, it had left the water and disappeared. Then I spotted it among the mud covered leaves climbing up the bank (I turned the picture sideways to make it fit the page better). Two shots were all I could take before it disappeared again, this time below the cliff I was standing on.
This is a garter snake (Thamnophis sirtalis). In the original post I had identified it as a ribbon snake (Thamnophis sauritus). However, one commenter indicated that it was instead a garter snake (see below). After I obtained confirmation from another source, I revised the post.