How does stream order relate to size? As
Thomas F. Waters notes in
Wildstream, a first order stream is
a mere trickle, fishable only by kids.
Fly-fishing anglers tangle their backcasts on
second or third order streams. Wading anglers
and canoeists share fourth and fifth order
streams. Most U.S. streams sixth order or
larger are dammed. The lower Mississippi, with
large tows of barges and even ocean freighters
rates tenth order.