Southeast Idaho Farmers Closely Watch Snowpack for American Falls Reservoir

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Southeast Idaho farmers are closely monitoring the water levels in the American Falls Reservoir and the region's snowpack, which will determine the availability of irrigation water for the upcoming growing season. The reservoir is currently only 57% full, while the broader upper Snake River reservoir system is at just 47% capacity - well below average. The snowpack in the American Falls watershed is closer to normal levels, but the Palisades Reservoir area has a below-average snowpack, raising concerns about spring runoff.

Why it matters

Adequate water supply from the American Falls Reservoir and the broader upper Snake River system is critical for the region's agricultural industry, which relies heavily on irrigation. Low reservoir levels and below-average snowpack could lead to water shortages and impact crop yields for local farmers.

The details

As of late January, the American Falls Reservoir was at 57% capacity, holding about 960,191 acre-feet out of its 1.67 million acre-foot capacity. The broader upper Snake River reservoir system was at just 47% capacity, well below average for this time of year. While precipitation and snow water equivalent have been above average in the American Falls watershed, the Palisades Reservoir area has a snowpack that is only 69% of normal. Warm storms have also pushed more moisture to fall as rain instead of snow, which can lead to earlier runoff and less long-term mountain storage.

• As of Wednesday, Jan. 28, the American Falls Reservoir was at 57% capacity.
• On Jan. 6, the upper Snake River reservoir system was reported to be at 47% capacity.
• Snowpack in the American Falls watershed is currently at 95% of normal, while the Palisades Reservoir area is at 69% of normal.

What’s next

Water managers will continue to monitor snowpack levels and reservoir storage throughout the winter and into the spring, as the spring runoff will be crucial in determining whether the American Falls Reservoir and the broader upper Snake River system can be fully recharged before the irrigation season begins.