One of the undertold stories, amid the gloomy forecasters for water in the southwestern United States, is the water conservation successes of the region’s major metro areas. Emily Green has a nice example from Los Angeles, where total water usage is down nearly 20 percent from 2006-07. Michael Cohen, at the Pacific Institute, documented this in an invaluable study back in 2011. But Cohen’s work captured something important. Even as per capita use is dropping, population growth is wiping out gains.

As I wrote in this morning’s newspaper, we’re seeing that play out right now in Albuquerque. After decades of drops in both per capita and total water consumption, the city’s water agency managers now are envisioning a future in which population growth begins to outstrip conservation gains:

Albuquerque’s water use is expected to rise 21 percent by 2024, as population growth outstrips conservation efforts, according to a new long-range plan approved Wednesday evening.

The Albuquerque Bernalillo County Water Utility board approved a new conservation strategy aimed at reducing per-capita consumption to 135 gallons per person per day by 2024, a 9 percent reduction from the current 148 gallons.

But with population in the utility’s service area projected to grow from the current 640,000 to 810,000 by 2024, overall water use is expected to rise, according to an analysis by Katherine Yuhas, the water utility’s conservation officer.