A new approach to time series analysis - the ORR method - was used to evaluate reconstructed western US streamflow records during 1500-2007. This method shows an interesting pattern of alternating drought and wet periods during the late 16th and 17th centuries, a period with relatively few drought or wet periods during the 18th century, and the and the reappearance of alternating dry and wet periods during the 19th and early 20th centuries.