Lake Mead is the largest man-made lake and reservoir in the United States. It is located on the Colorado River about 30 miles (48 km) southeast of Las Vegas, Nevada, in the states of Nevada and Arizona. Formed by water impounded by Hoover Dam, it extends 110 mi (180 km) behind the dam, holding approximately 28.5 million acre feet (35 km³) of water. The water held in Lake Mead is released to communities in southern California, via aqueducts, and Nevada.

The lake is currently filled to about 50% capacity due to drought conditions in the southwest United States. The white "bathtub ring" visible in the photograph shows the high water mark for the lake and results from mineral deposits left behind when the lake is at normal levels. There is concern that between climate change and over usage, the lake will eventually go dry.

For more information, see:

http://en.wikipedia.org/wiki/Lake_Mead
http://www.ens-newswire.com/ens/feb2008/2008-02-12-095.asp

And for my pictures of Hoover Dam see...

http://www.pbase.com/lmwalker/image/96817377