By Andrew Hay
May 7 (Reuters) – Colorado River flows into Lake Powell will hit record lows this summer after the lowest snowpacks ever recorded in the Rocky Mountain states of Colorado, Utah and Wyoming, according to a federal forecast on Thursday.
A March heatwave prematurely melted what snow fell during a warm, dry winter, leading to April through July Colorado River flows into Powell that will be only 13% of average, according to the Colorado Basin River Forecast Center.
That would make spring-summer runoff into Powell the lowest since the 1963 creation of the reservoir, which supplies water to 40 million people in major cities such as Los Angeles, Phoenix and Las Vegas.
“Really no good news this winter,” Cody Moser, a senior hydrologist with the center, said in a webinar.
The U.S. Southwest is caught in a decades-long megadrought in which rising regional temperatures, attributed by scientists to climate change, have caused aridification and falling stream levels.
It remains to be seen how low flows will impact the seven Colorado River Basin states that rely on the river.
The U.S. Bureau of Reclamation has started to cut water release from Lake Powell to stop it falling too low for hydroelectric production.
The seven river basin states are in long-running talks to reach a water-sharing deal this year or face an intervention by the federal government, which operates Powell and other reservoirs on the river.
Nevada, Arizona and California, the so-called lower-basin states, on Friday offered to increase their combined cuts in water use.
Eric Kuhn, a water researcher, expected state and local governments to impose additional outdoor water use restrictions to address any potential water shortages this year.
“I don’t see anyone that’s going to cut off water inside homes or fire hydrants,” said Kuhn, a former Colorado River water manager for the state of Colorado.
Phoenix has called for voluntary water conservation measures to address likely supply limitations. Los Angeles currently restricts outdoor watering with sprinklers to three days a week.
Looking ahead, a forecast strong El Nino weather system could improve flows in the lower basin with heavy summer monsoon rainfall. The weather phenomenon, a product of warm Pacific waters, typically causes wetter conditions in the southern United States.
(Reporting by Andrew Hay in New Mexico; Editing by Aurora Ellis)
