Idaho’s Water Supply Outlook – Water, Water Everywhere
BOISE– The Natural Resources Conservation Service has just released the fifth water supply outlook report for the 2017 water year. Precipitation since the water year started on October 1, 2016, is above or well above average across the state. The lowest amount is in the Clearwater basin at 123% of average and the highest is in the Little Wood and Big Lost basis at 182% of average.
The highest snowpacks in the state are twice normal in Idaho’s central mountains. The snowpack in the Big Wood basin above Hailey is 215% of average and record high since records start in 1961. The Little Wood and Big Lost are not far behind their record high years. Across southern Idaho the snowpack ranges from 140 to 180% of median. The exception is the Owyhee basin at 119% of median. Basins north of the Salmon River basin are about 115% of median. Even the lower elevations in eastern Idaho still have a good snowpack that is 185 to 200% of median in the Willow, Blackfoot and Portneuf drainages.
The May 1 streamflow forecasts call for extremely high volumes ranging from 150 to 270% of average from the Payette basin to the Upper Snake, and from the MF Salmon River to the Bruneau River across to the Bear River basin. The Clearwater streams are forecast around 115% of average and amounts increase to 145% for the Idaho’s Panhandle rivers.
Based on Idaho’s Surface Water Supply Index, “The challenge this year is not too little water – as all of Idaho’s 2,000-plus lakes and reservoirs will fill this year,” said Ron Abramovich, Water Supply Specialist for NRCS Idaho. “Rather, the concern is limited storage space if inflows continue to exceed outflows and fill the little remaining storage space.”