While not a waterway map, they are still the best around for the money...
Delorme is having a sale on their state topo/road/gazetteer map books for 50% off. These are, "amazingly detailed, large-format topographic & street map atlases of all 50 U.S. states. Unbeatable recreational information & detail."
Use priority code 9908 or use this LINK
They will charge you taxes and $5 shipping for orders under $50.
Hope this helps some of you!