A drought in the western United States has left water levels in the Colorado River basin far below their normal levels . Lake Powell , a reservoir at the Arizona-Utah border , is 45 per cent below its capacity , and the lack of water has left a 'bathtub ring ' at the bottom of its majestic rock formations . The lake , from which the Colorado eventually snakes through Grand Canyon National Park , has lost 4.4 trillion gallons of water in a recent drought . The river 's basin has been experiencing the drought for eleven of the last 14 years , shrinking a reservoir that was one-fourth the size of Rhode Island when it was at 'full pool ' , according to National Geographic . Scroll down for video . Lake Powell , which is the country 's second-largest reservoir when it is at 'full pool ' capacity , now has a white bathtub ring in its canyons from dropping water levels . The Colorado provides water for Nevada , Arizona and California , the last of which has seen large areas in 'extreme ' and 'exceptional ' drought levels and is trying to restrict how much water residents use . Seven states and 40million people get water from different parts of the river 's basin , which extends into the southern reaches of Wyoming . Many climate scientists think that the Southwest is also due for a megadrought this century that would far outlast the current phenomenon . Lake Mead , the reservoir next to Hoover Dam , shrunk to 39 per cent of its capacity last year and was at its lowest level since the dam was built in the 1930s . To help the other reserve keep a steady supply , Lake Powell will release 8.23 million acre-feet ( 2.68 trillion gallons ) downstream over the course of this year . The release is estimated to lower the water level at Powell , the second largest reservoir in the country behind Mead , by another meter . It is in danger of seeing its surface elevation fall below 1,075 feet above sea level by September , which would be the lowest level on record , set in 2005 , and increase the size of its bleached white ring . Minerals in the water turn the walls of the sandstone canyons white , according to the Weather Channel . Minerals in the Colorado River turned the sides of Lake Powell 's canyons white before the water levels dropped and the discoloration could be seen . Lake Powell provides water to Nevada , Arizona , and California , which has been experiencing its own drought problems . The reservoir is now at 45 per cent capacity after losing water from drought for most of the past 14 years . Around 40million people get water from different parts of the Colorado River basin , and Lake Powell ( pictured ) used to be one-fourth the size of Rhode Island . Lake Powell has lost 4.4 trillion gallons of water this century , rapidly decreasing in size from 1999 to 2013 . Sections of extreme drought have hit many states of the southwestern United States , including Arizona , Colorado , Nevada and California . The Colorado River basin stretches from the southern reaches of Wyoming to southwestern states such as Arizona ( pictured ) Lake Powell is a major Arizona vacation spot and draws more than 2million visitors to the reservoir each year . Sections of Lake Powell that used to be under water , such as this are of Big Water , Utah , now stand dry and pebbles from the riverbed are exposed . Lake Powell will release trillions of gallons of water through Glen Canyon Dam ( pictured ) so that Lake Mead , next to Hoover Dam , will not dramatically lose water levels . The diminishing of the Colorado River has exposed vegetation from the riverbed , such as that on this section around Horseshoe Bend . Motorboats can still navigate on some stretches of the river , though paddle boats are necessary for other parts . Water lines are visible on a section of Lake Powell that used to be under water but has now been exposed by a drought . Not all areas sport the white bath tub ring from where water used to be , though areas such as this part of Big Water , Utah , are also dramatically diminished from their surging heydays . Lake Powell reached a record low of 3555 feet in 2005 . Above , boaters tour the Cathedral in the Desert formations in 2007 . Scientists believe that the western United States may be due for a megadrought sometime this century . This map shows the severity of the drought in the western US , with 'exceptional ' drought in dark red , 'extreme ' drought in red and 'severe ' in orange . Drought levels are based off precipitation and moisture indices .
Eleven of the past 14 years have been droughts for Lake Powell reservoir . Reservoir at Nevada-Utah border is 45 per cent below 'full pool ' capacity . Lake will drop even further as it gives water to Hoover Dam 's Lake Mead .