Map #42: Index Value Plot

http://waterwatch.usgs.gov/?m=pa07d&w=plot

This portrays the average flow of a stream in the United States from 2001 to 2009. The higher the point, the wetter the stream, and the lower the point (under the solid straight line), the drier the stream. This is not a data graph for absolute numbers. Index is measured from climate differences or in the land's differences.