PHOENIX, March 9, 2012 - The Arizona Basin Outlook Report released this week by USDA’s Natural Resources Conservation Service (NRCS) shows the state snowpack to be at well below average levels. The federal agency monitors snow conditions in Arizona’s mountain watersheds each winter to estimate the amount of water available for spring and summer uses.
“Snow and rain accumulation in the mountains of northern and eastern Arizona has been well below normal since the beginning of the year,” said Dino DeSimone, State Water Supply Specialist with the NRCS in Phoenix, Arizona. “We are witnessing a repeat of last year with another La Nina winter. As a result, spring runoff is again expected to be at extremely low levels.”
Among the findings in the Basin Outlook Report, the Salt River basin snowpack was measured at 63 percent of the 30-year average; the Verde River basin at 47 percent of average; the San Francisco-Upper Gila basin at 75 percent of average; and the southern headwaters of the Little Colorado River basin had 60 percent of average snowpack. In the Chuska Mountains of northeastern Arizona, snowpack conditions were measured at 71 percent of average.
The current streamflow forecast calls for well below normal runoff over the March-May forecast period. Flows over these three months, typically the time of year when the greatest runoff occurs from snowmelt, is expected to be only 27 percent of median on the Gila River; 37 percent on the Salt River; 31 percent on the Verde River; and 40 percent on the Little Colorado River. The Colorado River inflow to Lake Powell, which reflects snowpack conditions in the Upper Colorado River Basin, is estimated at only 67 percent of average for the forecast period April-July.
As of March 1st the six Salt River Project reservoirs held a combined total of 1,523,300 acre-feet (a-f) in storage at 66 percent of system capacity. San Carlos reservoir held 24,300 a-f storage, which is only three percent of capacity. Storage in Lyman Lake was 9,600 a-f. The combined storage of Lake Mead and Powell on the Colorado River was 30,360,000 a-f, which is 60 percent of combined capacity. An acre foot of water equals 325,851 gallons and is enough to supply a family of five for a year.