...The graph shows Lake Powell’s water level from 2000 to 2007, measured in millions of acre-feet. This measure of lake volume counts the acres of land surface covered by a foot of water. The water level from May 2006, superimposed onto the satellite image, had actually rebounded somewhat from the 2005 low. After peaking in late 2000 with more than 20 million acre-feet, the reservoir’s water level sharply declined to roughly 8 million in mid-2005....
Part of the problem with The Powell Dam is it was constructed in the worst area of the country possible. It's banks are imbedded in Navaho Sandstone. Navajo Sandstone is porous and requires water to saturate the holes in the rock before the lack level rises.
