For the past five years, the drought that has parched much of the West has become increasingly difficult to handle.
Continuing research into drought cycles over the last 800 years strongly suggests that the relatively wet weather across much of the West during the 20th century was a fluke. In other words, scientists who study tree rings and ocean temperatures say the development of the modern urbanized West may have been based on a colossal miscalculation.
That shift is altering many perceptions about how the West is run. Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming, the states most dependent on the Colorado River, are preparing for the possibility of water shortages for the first time since the 1930s, when Hoover Dam was built to control the river's flow.
Paltry snowfall during March in the Rocky Mountains pushed down runoff projections for the Colorado River this year to 55 percent of average. Snowmelt is the lifeblood of the river, which provides municipal water from Denver to Los Angeles, irrigating millions of acres of farmland.
The period since 1999 is now officially the driest in the 98 years of recorded history of the Colorado River, according to the U.S. Geological Survey.
Some of the biggest water worries center on Lake Powell a vast blue diamond of deep water that government engineers created in one of the driest and most remote areas of the country beginning in the 1950s. It is the nation's second-largest artificial lake, after Lake Mead in Nevada.
From its inception, Lake Powell was a powerful symbol across the West. Powell has lost nearly 60 percent of its water and is now about the size it was in 1973, when it was still filling up.
Many past Western droughts have ended suddenly, with a bang of precipitation. But some dry spells persisted for generations.
Options currently under consideration to save water on the Colorado River include the following:
Create a water bank in Lake Mead shared by Arizona, California and Nevada. Regulations for interstate water banking were drafted in the mid-1990s. Cooperation required from all three states.
Crack down on Colorado River farmers who purposefully overuse their water entitlement to avoid coming up short and on unauthorized users who tap into river.
Emphasize desalination technologies.
Shift storage of water from Lake Mead, where temperatures reach 120 degrees, to Lake Powell, where there's less evaporation, or other upstream reservoirs.
Construct off-stream reservoirs to recoup excess water flows that would otherwise be lost. A $60 million project in California's Imperial Valley is being constructed and funded by U.S. Interior Department and Metropolitan Water District of Southern California.
Examine making better use of flash-flood water on Colorado River and tributaries by storing it in surface reservoirs or groundwater basins in the United States or Mexico.
Start up Yuma Desalting Plant, a facility constructed to satisfy U.S.-Mexico treaty, and eliminate agricultural runoff running into Mexico.
Encourage cities to pool money to pay to have water-saving technologies installed in agricultural areas.