A new study out today from the Pacific Institute of municipalities’ water use in the Colorado Basin has some good news and some bad news from a basin-wide perspective.

Per capita water consumption in the basin’s cities is down:

Almost every one of the water agencies included in the study experienced declines in per capita deliveries from 1990 to 2008. People and business are demanding less water than they did in 1990.

But rapid population growth in the arid region has more than outstripped the savings:

The number of people relying at least in part on water from the Colorado River basin increased by roughly 10 million people from 1990 to 2008, to a total of almost 35 million. Much of this increase occurred in areas experiencing extraordinary population growth: several cities in Arizona and Utah more than tripled in population between 1990 and 2008. The Las Vegas metropolitan area added upwards of a million people, more than doubling in size. Tijuana also roughly doubled in size, adding more than 800,000 people reliant on Colorado River water for an estimated 90 percent of their water supply.

Total water deliveries by these 100 agencies increased from about 6.1 million acre-feet in 1990 to about 6.7 million acre-feet in 2008. The volume of Colorado River basin water deliveries by these agencies also increased by about 0.6 million acre-feet over this period, from 2.8 million acre-feet to 3.4 million acre-feet, rising from 46 percent to 51 percent of total deliveries.

As I noted in my story in the morning paper (sub/ad req.), Albuquerque is a relative bright spot, with conservation efforts since 1990 outpacing population growth.

(Kudos to Cohen and the Pacific Institute for assembling an incredibly valuable set of data.)