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“Civilization exists by geological consent, subject to change without notice.” — Will Durant

I just saw a very somber, but beautiful mini-documentary about the Colorado River called Chasing Water by photo journalist Pete McBride. It is the highest utilized river on the planet relative to irrigation and human consumption. Once hailed as a wonder of the world and North America’s greatest estuary, the Colorado River Delta is now a barren wasteland:

In 1922, the great naturalist Aldo Leopold canoed through the delta, which he described as “a milk and honey wilderness” and a land of “a hundred green lagoons.” It was home back then to deer, quail, raccoon, bobcat, jaguar and vast flocks of waterfowl, and its 2-million-acre expanse was a crucial stopover on the Pacific flyway, providing respite and feeding grounds for millions of migratory birds as they journeyed across the western Americas.

Fisheries in the upper Gulf of California depended on the Colorado delta too. The totoaba, a relative of white sea bass that could grow to more than 250 pounds, would migrate from the upper gulf to spawn in the delta’s brackish estuaries. For at least 1,000 years, the indigenous Cucapá, the “people of the river,” fished and farmed in the delta, keying their lives to the river’s ebb and flow.

Today, the Colorado delta is a shadow of its former self. Once one of the planet’s most vital aquatic ecosystems, it is now one of the most threatened. A low-altitude flight over the region reveals a desiccated landscape of salt flats and cracked earth. There is little sign of a living river because the river is gone; in all but the wettest years, it disappears into the desert sands a short distance south of the border.

Its waters are siphoned off by several states, the lion’s share going to California. According to a study last year by the Bureau of Reclamation, the reliability of this water flow is not going to hold up into the future. Quoting from a recent article in the National Geographic, the results of the study are profound:

Last year the Bureau of Reclamation finalized their first assessment of climate change impacts on Colorado River flows, concluding they would most probably decline by 8.7% by 2060.  That’s a loss of 1,300,000 acre-feet, the entire annual capacity of the canal diverting water to Los Angeles, Orange, and San Diego counties.

Now we have confirmation from Reclamation that whatever water is left in the Colorado River won’t go as far.  Hotter temperatures will drive an increase in water demand.  The average projected increase in water use, based solely on temperature increases, is 500,000 acre-feet.

In simple terms, increased temperatures mean that every living thing will need more water to survive.  This includes all the lawns we water and all the crops we grow with Colorado River water.

Reclamation hasn’t put these two numbers together yet in a public document, but the result is profound.  The climate change impact on Colorado River water translates into a decrease in supply and an increase in demand totaling a deficit of  1,800,000 acre-feet.  Keep in mind, this is just the average, not the worst case.  Moreover this is just the deficit created by climate change, and does not account for the inevitable increase in water demand by a growing regional population.

In his book Dead Pool, author James Lawrence Powell says that the Bureau of Reclamation and politicians used flagrant exaggerations of not only construction costs, but also water flows in order to facilitate the building of dams along the Colorado River. Taxpayers were left with the bill for overpriced dams which delivered water costing far more than the value of the crops it fed. The massive Western water projects amounted to what Powell calls a “a kind of hydraulic Ponzi scheme.”

The Bureau’s Colorado River Compact promised more water to the various states than what the river could realistically deliver because its water-flow projections were based on measurements of a period before 1922 during the ‘wet years’ when the river’s annual flow averaged 21 million acre-feet (MAF).

Even though current Colorado River allocations are based on a presumed annual flow of 16 MAF, historical records taken partially from tree-ring studies show the Colorado River to have an average of only 14.6 MAF per year over the last four and a half centuries. If you couple these findings with that of the climate change predictions discussed above, then unless there is some new miracle for conserving a massive amount of water, a mass exodus of the population from the Southwest seems likely over the next several decades. Making matters worse, the Southwest is the fastest growing region in the country. Climate change has already had a visible effect on the Southwest’s water supply, says Powell:

The flow of the Colorado River during the twenty-first century dropped so much faster than the experts thought possible that by 2004, Lakes Powell and Mead together held 20 MAF less than their worst-case forecast. …Including the relatively wet 2005, the average inflow to Lake Powell during the first eight years of the twenty-first century is down by an average of 40 percent [from the twentieth-century average].

Others are already seeing the handwriting on the wall with climate refugees here in the U.S.:

No one has a crystal ball. But it is now predicted that the Southwest will experience a permanent drought, far worse than the 1930s Dust Bowl. That may cause massive population migration in a breathtakingly short period of time (in the next four decades), as the arable water supply from Kansas to California dries up. University of Arizona studies indicate that if greenhouse gases continue to go unchecked, the overused Colorado River – which supplies municipal and agricultural water to seven western states – may be reduced to half of its current flow under a plausible worst-case scenario.

…Millions of displaced Americans could be on the move. They will not be the first climate refugees in the world, nor the last, but they certainly will be knocking on our door.

Other readings:

Reading L.A.: Marc Reisner’s ‘Cadillac Desert‘