NEWS

U.S. Department of Agriculture
Natural Resources Conservation Service
9173 W. Barnes Dr., Suite B
Boise, Idaho 83709

For more information:
Ron Abramovich (208) 378-5741
 

Idaho Water Supply Outlook Still Marginal

Boise, ID, January 7, 2005—The water supply outlook in Idaho remains marginal as we approach the winter’s half-way point in mid-January, according to the Idaho Water Supply Outlook Report issued this week by the Natural Resources Conservation Service (NRCS).

Well above average precipitation in October was followed by well below average precipitation in November, 25 percent of average in the central Idaho mountains. December’s precipitation was near average and fell in the beginning and at the end of the month. The Bear River Basin received the highest precipitation levels at 114 percent of average while the West Central Mountains and Salmon River Basins received the lowest at 72 percent.

Most Idaho snowpacks are below the January 1 average once again and also are considerable shallower than the snowpacks last year at this time. Several major basins including the Clearwater, Salmon, Payette, Snake above Palisades and Owyhee fall in the 60 to 80 percent of average range.

“We’re excited to see snow forecasted for much of Idaho this weekend,” says Ron Abramavich, NRCS water supply specialist. “But we’ll need to see a continued accumulation throughout the winter before it will significantly impact the drought.”

The cumulative five-year drought effects are still impacting Idaho’s reservoir storage. Reservoir levels remain well below average in southern and eastern Idaho. While many North Idaho reservoirs are in better shape this year, the Boise Reservoir system is only at 38 percent of capacity. Magic, Bear Lake and Blackfoot Reservoirs are only at 10 percent capacity. Most other southern and eastern Idaho reservoirs are at below 50 percent of capacity.

• Panhandle—Precipitation since the water year started October 1 is 85 percent of average and less than last year at this time. Snowpacks in this region are the lowest in the state ranging from 53 percent of average in the Spokane Basin to 75 percent in the Kootenai Basin. Precipitation that is 30 percent above average is needed to reach average snow levels by April 1.
• Clearwater River—Overall, snowpack is 62 percent of average, which is slightly more than half of last year’s snowpack on January 1. An index of 13 snow stations show this year’s snowback to be the seventh lowest since 1961. The Clearwater River Basin is directly impacted by El Nino, the cause of the current low snowpacks. However, the same El Nino scenario happened in 2003 and, by April 1, snowpack had increased enough to make the season near average.
• Salmon River—Overall, snowpack is 76 percent of average, about three-quarters of last year’s January snow. To reach a near average snowpack by April 1, precipitation that is 20 percent above average is needed for the rest of the winter.
• Weiser, Payette, Boise River—Water year to date precipitation is 72 percent of average, about three-fourths of last year. Snowpacks range from 70 percent of average in the Payette and Mann Basins to 85 percent in the Boise and Weiser Basins. Precipitation that is 20 percent above average is needed to reach normal snow levels by April 1. Currently, the Boise Basin snowpack is the lowest since 2001, when the April 1 snow peaked at only half of average.
• Wood and Lost River—Water year to date precipitation is 92 percent of average, the same as a year ago. The difference in precipitation is that more of it fell as rain this year soaking into the ground and improving soil moisture conditions.
• Upper Snake River—Water year to date precipitation is 88 percent of average, which is less than last year at this time. December and January are the mountains’ biggest precipitation months with snow stations in Yellowstone National Park receiving 7-8 inches each month. Average or better precipitation is critical in the next few months, otherwise the snowpack will continue to decrease.
• Southside Snake River—Water year to date precipitation is slightly higher than average in the Oakley Basin at 103 percent and decreases to 97 percent in the Salmon Falls Basin, and 93 percent in the Bruneau and Owyhee Basins. The snowpack mirrors these trends with near average snow water content amounts in the Raft, Oakley and Salmon Falls Basins, 90 percent in the Bruneau Basin and only 68 percent in the Owyhee.

Bear River—Water year to date precipitation is 114 percent of average and is better than a year ago. The snowpack is near average and is currently 40 percent of the seasonal peak that occurs in April. Because of the cumulative drought, above average snowfall is still needed the rest of the season.

For the complete Idaho Water Supply Outlook Report, visit www.id.nrcs.usda.gov/snow.

USDA is an equal opportunity provider and employer.

< Back to News Releases