Tuesday, January 24, 2012
Arizona's thirsty cities
Phoenix and Tucson get much of their water from the Central Arizona Project, "the country's largest and most expensive water-delivery system," according to an excerpt from a new book, "The Very Hungry City," by Austin Troy [right, CAP system map, from the book].
Troy notes that CAP relies on the Navajo Generating Station, a coal-fired power plant at Page, to supply the electricity to run 14 pumping stations that "are required to keep water moving along this 336-mile infrastructural straw, which includes a rise of 3,000-feet in its journey from Lake Havasu to southwest Tucson." Pumping costs account for 42% of waters cost to CAP users, and they have no where else to turn for electricity. As a result he argues that "the future price of energy — and hence of water — is bound to the price of coal." And the availability of coal as a fuel source for NGS, a subject of debate over air quality issues.
The availability and cost of water has a big impact on certain Arizona industries. While agriculture is generally considered the largest water user, Troy points out that Intel is Phoenix's biggest water consumer, using 7 million gallons a day in its computer chip manufacturing facilities, but cleaning and returning 3/4 of its wastewater back into the aquifer, for a net use of 2 million gallons daily. He raises the question whether new industries will consider setting up in Arizona, if they are similarly dependent on water supplies.
He predicts a time when agriculture and urban water users will have to square off: "But most water in the West is now used to irrigate crops; city dwellers get what’s left. And in these arid lands agriculture has been subsidized for decades through the provision of water below the cost of delivery. There may come a time when western water managers will need to ask whether desert agriculture — a vital source of America's food supply — is worth the cost."
The excerpt that I read came across as honest and frank in its assessment. Troy leaves it to the reader to make his/her own judgement although the description he offers leads one to appreciate the fragility of maintaining cities in the desert. I appreciated the focus on solid information without overt proselytizing or polemics.