6-18 FB Water Supply

Crazy Weather Affects Water Supply Forecast

The final water supply report from the Natural Resources Conservation Service predicts water supplies could be tight in some basins in southern Idaho this summer based on streamflow forecasts. Here is Ron Abramovich, Water Supply Specialist with Idaho NRCS: “Idaho’s reservoirs are worth their weight in gold this year. Carryover water storage from last year will help southern Idaho farmers get through the irrigation season; however, ranchers depending on natural streamflow to water rangeland pastures may suffer after such a dry winter.”
     According to Abramovich, there is good reservoir carryover storage for Upper Snake water users, but streamflow forecasts are at 77% of average for the Snake River near Heise. This could make for tight water supplies by summer’s end depending on summer weather and irrigation demand.
     “The Big and Little Lost River watersheds may also have marginally adequate water supplies,” said Abramovich. “But I’m hopeful the high ground water levels and near average streamflow forecasts for the Big Lost and Little Lost rivers, will help sustain stream flows into the summer. May precipitation can be described as average, fair, and poor depending on what part of the state you are in,” said Abramovich. “The worst rainfall measurements were in southern Idaho’s desert basins, like the Owyhee, Bruneau, and Salmon Falls, which received 50% of average. Streamflow forecasts are also poor for these areas ranging from 15 – 50% of average. A cool summer with moderate temperatures would stretch this year’s water supply in southern Idaho.”
     North Idaho is better off, May precipitation ranged from 85-100% of average and June 1 snowpacks are 109 to 130% of average.