The high water mark for Lake Mead is seen on Hoover Dam and its spillway, Tuesday, April 16, 2013, near Boulder City, Nev. Citing drought and demand, advocacy group American Rivers is c

 

              The high water mark for Lake Mead is seen on Hoover Dam and its spillway, Tuesday, April 16, 2013, near Boulder City, Nev. Citing drought and demand, advocacy group American Rivers is c
The high water mark for Lake Mead is seen on Hoover Dam and its spillway, Tuesday, April 16, 2013, near Boulder City, Nev. Citing drought and demand, advocacy group American Rivers is calling the Colorado River the nation's most endangered waterway. The group's annual report follows a federal Bureau of Reclamation study that says that over the next 50 years the Colorado River will run short of supply for the more than 40 million people it serves in Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming. (AP Photo/Julie Jacobson)