Per-capita water use has declined in 100 communities that depend on the Colorado River, the primary source of freshwater to much of the southwest. But as populations expand, overall water consumption is still climbing.
Jeff Robbins / AP / File
Water conservation efforts in the western US over the past 20 years appear to be paying off.
Major communities that rely partly or completely on the Colorado River for their water have reduced per-capita demand on the river an average of 1 percent or more each year between 1990 and 2008, according to a new study. In all, that's some 2 million acre-feet of water saved – enough to supply Los Angeles for about three years.
But as populations grow, per-capita efficiency isn't enough. Communities are still siphoning ever-larger amounts of water from the river.
During the study period, the volume of water drawn from the Colorado River – by 100 municipal and regional water authorities – grew by 5 percent, even as the amount they drew from all sources rose by 10 percent, according to the report, which was issued Thursday by the Pacific Institute, a water-resource policy group based in Oakland, Calif.
The increased demand was fueled by a population that blossomed from around 25 million in 1990 to 35 million by the end of the study period.
Still, the steady decline in per-capita demand is noteworthy, says Michael Cohen, a senior research associate with the Pacific Institute and the author of the study.