Recently Stephen Von Worley created a series of beautiful maps, Crayon the Grids, in which the U.S.'s roads were colored by orientation. Andrew Hill has created a similar map of U.S. Rivers Colored by the Direction they Flow. Need more info? Visit convert illustrator to pdf in free Vector Map of USA with State Names, in Adobe Illustrator and PDF.
The map uses data from Nelson Minar's Vector River Map, which in turn uses river flow data from
NHDPlus. Andrew has also used the same river data to create another beautiful map. Rivers with Rainfall. This map shows U.S. rivers and rainfall in the last hour. The rain data comes from a National Weather Service data feed. Source