Scientists say the drought in the western region of the US is the worst in hundreds of years. At Lake Mead the reservoir is only 28% full. The other reservoirs on the Colorado river are in similar shape. Lake Mead is a reservoir from the Hoover Dam on the Colorado River and stretches for 120 miles in the states of Arizona and Nevada. It is the largest reservoir in the US and the water depletion in this and other reservoirs all the way into Oregon is affecting agriculture in the western US and the access to water for cities in the region.