Population and Water in the West

A few days ago the New York Times did a story on the drought in the Colorado basin that has led to the Colorado River being at an historic low level. There are seven states that use water from the Colorado River (five in the the US--Colorado, Utah, New Mexico, Arizona, and New Mexico) and two in Mexico (Sonora and Baja California Norte), so the river is mightily important. As a resident of California, the most populous state in the US, this is obviously important to me personally. Here in San Diego where I live, we have enough water of our own to service only 10 percent of the population, so importing water is obviously a key issue. At the same time, we have to import energy and food, as well, so the region is certainly not self-sustaining. These are not new issues, though, and I wouldn't have given them much thought were it not for a letter to the editor about the article from Stan Becker, a demographer at Johns Hopkins University. He's a good demographer and so I paid attention to the thrust of his argument:

However, as is typical of such news reports, the article does not directly deal with the elephant in the room — rapid population growth in the Southwest — except to take continued growth as given. It merely says “40 million people also depend on the river and its tributaries, and their numbers are rising rapidly.”

Is it not appropriate to openly ask two questions: What is a sustainable population in the Southwest, considering its water resources, and what policies could eventually limit population growth there?

The bottom line is almost certainly the cost of water. It is expensive to dam the river, pump water out of it, and send it off to reservoirs where it will be treated and then consumed. People use water more efficiently as its cost rises, and more conservation is the most reasonable way to spread the same or lower amount of water around a growing--albeit it a slower rate than in the past--population. Professor Becker notes with seeming approval the building of a desalination plant in San Diego, but that is not a real alternative because the cost of energy is so great and there are serious environmental issues near the plant. Indeed, it is reasonable to suggest that the inland areas of the southwest are as dependent upon air conditioning as they are on water, and as the cost of energy rises (even with alternative sources such as solar and wind) that may be as much a retardant to population growth as will be scarcity of water.