Minidoka County Water Intelligence Brief

September 28, 2026 | Agricultural Water Management Edition

Situation Summary

Snake River flows at the Howells Ferry gauge (USGS 13081500) are holding at 4,000 cfs and stable as of September 28 — a late-season baseline that reflects the tail end of the 2026 irrigation season for Minidoka Irrigation District deliveries from Lake Walcott. With potato and sugar beet harvest underway and dairy operations maintaining continuous demand, irrigators should monitor whether current flow levels are sufficient to sustain any remaining delivery obligations through season close. Reservoir storage data for Lake Walcott and 7-day forecast details are available in the full brief.

Snowpack Conditions

Lewis Lake Divide (SNOTEL) recorded 0.0" snow water equivalent and 0.0" snow depth as of September 27. No below-normal signal is present — the historical median SWE for this date is also 0.0", so the station is at its normal seasonal condition for late September. The relevant 2026 snowpack story is timing: the snowpack that fed this year's Snake River runoff melted out 4–6 weeks ahead of the historical median meltout date, driven by an anomalous March heat wave. That early meltout shaped the summer supply trajectory and is now background context as the irrigation season winds down.

Streamflow Conditions

The Snake River near Minidoka at Howells Ferry (USGS 13081500) is reading 4,000 cfs and stable as of September 28. This gauge reflects Snake River delivery to Minidoka County before any downstream Milner Dam diversion — it is the upstream supply signal for the Magic Valley corridor and a leading indicator for conditions that will appear at Milner weeks later. A stable reading at this point in the season indicates the river is maintaining late-season baseflow, though 4,000 cfs reflects post-peak conditions typical of September drawdown. Irrigators and Minidoka Irrigation District staff should track whether flows hold, flatten further, or begin declining as upstream storage releases wind down.

Seasonal Guidance

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Data Sources: SNOTEL data through September 27, 2026; USGS streamflow data through September 28, 2026

Data Current As Of: September 28, 2026 | Idaho Department of Water Resources, Eastern Regional Office, Pocatello — (208) 525-7161

Important Disclaimers: This brief provides automated analysis for informational purposes only. Specific numerical claims have not been independently verified. Consult official sources including your local water district, U.S. Bureau of Reclamation Pacific Northwest Region (Boise office — operates Minidoka Dam and the Minidoka Project, including Lake Walcott), Minidoka Irrigation District (primary delivery entity receiving water from Minidoka Dam diversions), Idaho Department of Water Resources (IDWR — administers Water District 36, middle Snake River), and U.S. Bureau of Reclamation for American Falls Reservoir and Palisades Reservoir upstream context for regulatory decisions and water rights administration.