Reconstructed Naturalized Colorado River Flow at Lees Ferry Near Page, Arizona

Reconstructed Naturalized Colorado River Flow at Lees Ferry Near Page, Arizona: Time series plot of past Colorado River flows created by analyzing tree-rings. The plot displays the 25-year running average of the reconstructed flows. Flows are plotted as a percentage of the 1906–2004 average of observed natural flows (18.5 billion cubic meters or 15.0 million acre-feet). The red horizontal line is the lowest 25-year running mean of observed flows (1953-1977).

Credit: Dave Meko, Laboratory of Tree-Ring Research, University of Arizona. http://www.ltrr.arizona.edu/