I took this picture of the C&O Canal at Georgetown on 18 September. The Canal had been mostly without water at least since early September when I first started exploring the area (see this post).
Here is a picture I took from roughly the same spot on 9 October.
Where did all that water come from? We certainly haven't had enough rain to fill the Canal. The Park Service must have a way of bringing water from the Potomac River which is below and quite close to the Canal.