First Arizona NRCS 2008 snow pack report: Close to 30-year average, normal spring runoff expected

Water resources specialists from the Arizona Natural Resources Conservation Service (NRCS) and cooperating partners are forecasting normal spring runoff in Arizona’s major rivers and streams based on recent snowpack measurements in Arizona’s mountain watersheds.

Statewide, the January 1 snowpack measured 93-percent of the 30-year average, compared with 38-percent a year ago. The Salt River and San Francisco-Upper Gila River Basins have slightly above normal snow levels for this time of year, but the Verde River and Little Colorado River Basins are below normal for January 1.

After low snowpacks last winter, recent snowstorms in December raised the hopes of water users, but NRCS water resources specialist Dino DeSimone cautions it will take several more heavy winter storms to build the state’s snowpacks to levels that will produce normal stream flows during the spring snowmelt season.

“The upcoming winter snowpack measurements will provide the best prediction of whether we are headed towards another dry year or more normal conditions,” said DeSimone.

On the Verde River at Horseshoe Dam, the long-term runoff prediction calls for 100 percent of median stream flow levels (220,000 acre-feet) for the January-May forecast period.

On the Salt River near Roosevelt, the runoff forecast calls for 117 percent of median stream flow levels (450,000 acre-feet), January 1 through May, while on the Gila River at San Carlos, inflow to the reservoir is forecast at 110 percent of median stream flow (105,000 acre-feet) January 1 through May.

In the Little Colorado River above Lyman Lake, the forecast calls for 127 percent of median stream flow January 1 through June.

As of January 1, the combined Salt River Project (SRP) system is at 60 percent of capacity with 1,389,399 acre-feet in storage. The SRP system covers the Verde and Salt River watersheds and includes six reservoirs; Horseshoe and Bartlett, both on the Verde River, and Roosevelt, Apache, Canyon, and Saguaro, all on the Salt River. At San Carlos, reservoir storage stands at 177,800 acre-feet, or nearly 20 percent of capacity.

NRCS makes snow measurements throughout the winter to forecast and track the state’s surface water supplies for the coming year. As a result of these snow measurements, an Arizona Basin Outlook Report is developed and issued every two weeks beginning January 1 through April 1. The report is used by farmers, ranchers, municipal water suppliers, and other water users to help manage limited water supplies.

The snow survey season began January 1, when the NRCS, U.S. Forest Service, National Park Service, and the Navajo Nation began manual measurements of snow depth and snow water content at 23 snow courses across northern and eastern Arizona. The same locations are measured each year, for over 50-years in some locations.

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