Earth Protect Blog

Water scarcity has always been a problem in the southwestern desert, with practically everyone relying on one river, the Colorado, to quench their thirst and the thirst of their crops. Increased water demands coupled with a long protracted drought in the Upper Colorado River Basin has created a potentially dire situation. The effects can be seen in Lake Mead, the giant lake along the border of Arizona and Nevada. Lake Mead has reached its lowest levels since 1937, the year the Hoover Dam was completed.

Lake Mead is the largest reservoir in the United States, created from the construction of the Hoover Dam. It is the primary source of water for much of Nevada and Arizona. Many times, it has fallen below drought level (1,125 feet above sea level). In June of 2010, the lake was at only 39 percent of its holding capacity. As of October 17, it reached its lowest level in nearly 75 years as its high-level mark fell to 43 feet below drought level to 1,083 feet above sea level.
The fastest growing region in the US is the southwest.. Unfortunately, it is the region that can least afford massive population increases. Places like the Las Vegas metropolitan area in Nevada and the Valley of the Sun in Arizona have grown by leaps and bounds in past few decades. Phoenix is now the nation's fifth largest city. Recent economic turbulence may have put a damper on that growth, but the higher water demand is still there.

Increased demand is a key factor, but perhaps not as important as the lack of rainfall across the southwest which feeds Lake Mead. According to the US Department of the Interior's Bureau of Reclamation, the Upper Colorado River Basin has had only 89 percent of its average precipitation for 2010. They predict that this autumn, the temperature will remain above average and precipitation below average, leading to worsening conditions.
The current drought began way back in October 1999. At that point, Lake Powell, the second largest reservoir in the US located along the Arizona-Utah border, was near full capacity. Over the next five years, inflow into the lake was about half of the average. It has increased somewhat since then, but remains low.

http://www.enn.com/climate/article/41909