Colorado River Past and Future Drought

Colorado River Past and Future Drought



Feb 2007 - The Colorado 
River's average annual flows vary more than previously assumed 
and extended droughts are not uncommon, according to a report 
released Wednesday by the National Research Council. The 
conclusions, based on tree-ring reconstructions of the river's 
flow over hundreds of years, indicate that future droughts may 
be longer and more severe because of global warming. 
The report found ample evidence suggesting that rising 
temperatures will reduce the river's flow and water supplies 
and warns that coping with water shortages is becoming more 
difficult because of rapid population growth. 
Technology and conservation will not provide a panacea for 
dealing with limited water supplies in the long run, the 
report warns. 
The findings are a stark reminder of the need for better 
management of the water resources of the Colorado River, which 
provides water for tens of millions of Americans as well as 
for agriculture and hydroelectric power. 
The river also is home to diverse ecological habitats and is 
central to hundreds of miles of beautiful vistas that it 
carved out over millions of years, including the Grand Canyon. 

The National Research Council conducted the study in response 
to exceptionally dry conditions in much of the Colorado River 
basin in recent years. 
The committee also looked at how a steadily rising population 
and related increases in water demand will affect Colorado 
River water management. 
The population across the western United States has grown 
rapidly in recent decades - Arizona saw a roughly 40 percent 
rise in population since 1990, for instance, while Colorado's 
population grew by 30 percent in the same period. 
Increasing urban demands for water are often met through 
sales, leases, or transfers of water rights from agricultural 
users. Although 80 percent of available water in the West is 
devoted to agriculture, this allocation is finite, the 
committee warned, and water transfer agreements will be 
limited in their ability to satisfy growing, long-term demand. 

In addition, such agreements may be inhibited by their 
potential effects on third parties, such as downstream farmers 
or ecosystems. Technology and conservation measures are useful 
and necessary for stretching existing water supplies, the 
committee acknowledged, but any gains in water supply will be 
eventually absorbed by the growing population. 
The committee called for a collaborative, comprehensive 
basinwide study of urban water practices and pressing issues 
in water supply and demand, which should be used as a basis 
for action oriented water planning.

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