NEWS

United States Department of Agriculture
Natural Resources Conservation Service
9173 W. Barnes Dr., Suite C
Boise, Idaho 83709

For more information:
Ron Abramovich phone 378-5741
 

IDAHO WATER SUPPLIES SLIP TO BELOW NORMAL

BOISE, MAR. 8—The lack of new snow in February has taken its toll on Idaho’s frozen liquid gold. Streamflow forecasts decreased 5 to 20 percent points across most of the state as a result of below normal precipitation in February, according to the Idaho Water Supply Outlook Report issued March 1 by the Natural Resources Conservation Service.

Streamflow forecasts range from a high of 120 percent of average in northern Idaho to 42 percent of average in the Bear River Basin in southeastern Idaho. Most streams across central and eastern Idaho are forecast in the 75 to 85 percent of average range. Based on below normal runoff volumes Palisades, Jackson Lake and Anderson Ranch reservoirs are not expected to fill.

Irrigation water supplies are expected to be marginally adequate for the year.

The Panhandle Region and Clearwater Basin received the most February precipitation at 80 percent of average. The Bear River Basin in southeastern Idaho received the least at only 41 percent of average. Elsewhere, precipitation ranges from about 55 percent of average in the Salmon and west-central mountains to 45 percent in central, eastern and southern Idaho.

Despite the decreases in snowpack percentages and streamflow forecasts, the water year is still better than a year ago when snowpacks were 45 to 55 percent of average and resulted in summer streamflows that were 30 to 60 percent of average.

Normal or better precipitation is needed during the next six weeks to ensure adequate irrigation water supplies. There should be enough water for river runners, boating and fishing.

Streamflow Forecasts by Basin

Panhandle Region: 90 to 120 percentage of average. Water supplies will be adequate and much better than last year.

Clearwater River Basin: Dworshak Reservoir inflow is forecast at 112 percent of average and will fill this year. The Clearwater River at Spalding is forecast at 110 percent of average. The Selway and Lochsa Rivers are forecast at 89 percent and 96 percent of average respectively.

Salmon River Basin: The Salmon River at Salmon is forecast at 86 percent of average. The Salmon River at White Bird is forecast at 89 percent of average. The Middle Fork Salmon River has twice the amount of snow as last year.

Weiser, Payette, Boise River Basins: Payette River near Horseshoe Bend is forecast for 90 percent of average. The Boise River near Boise is forecast for 88 percent of average. Lucky Peak and Arrowrock Reservoirs are projected to fill. Anderson Ranch Reservoir is not projected to fill. Water supplies should be adequate.

Wood and Lost River Basin: Magic Reservoir is nearly empty at 10 percent of capacity; streamflow forecast is 78 percent of average. Water supplies will be marginally adequate. Little Wood Reservoir is 37 percent full with a streamflow forecast of 78 percent. Water supplies will be adequate. Mackay Reservoir is 50 percent full with a streamflow forecast of 77 percent of average. Water users may experience irrigation water supply shortages. The Little Lost River is projected at 84 percent of average. Irrigation water shortages could occur.

Upper Snake River Basin: Streamflow forecast range from 60 to 80 percent of average. Palisades Reservoir and Jackson Lake will not fill based on these below normal projections. Irrigation water supplies will be marginally adequate. Water users should prepare for possible shortages, depending on water rights and water sources.

Southside Snake River Basins: Salmon Falls Reservoir is nearly empty at 8 percent of capacity. Inflows are forecast at 81 percent of average. Oakley Reservoir is 19 percent of capacity with inflows projected at 76 percent of average. The Snake River at Hells Canyon is forecast at 64 percent of average. Oakley and Salmon Falls water users should prepare for irrigation water shortages, especially if spring precipitation is below normal.

Bear River Basin: Streamflow forecasts decreased significantly from February and call for much below normal runoff volumes at only 42 percent of average for the Bear River below Stewart Dam. Bear Lake irrigators can expect water supply shortages, especially if conditions remain dry.
   

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