Minidoka County Water Intelligence Brief

September 7, 2026 | Agricultural Edition

Situation Summary

Snake River flows at Howells Ferry are running at 6,970 cfs as of this morning — a stable reading that reflects late-summer baseflow conditions typical for this point in the irrigation season, with snowmelt contribution long exhausted and the river now sustained primarily by reservoir releases and groundwater return flows. For Minidoka Irrigation District deliveries drawing from Lake Walcott, the near-term operational question is how Minidoka Dam storage is tracking against remaining seasonal demand from potatoes, sugar beets, and alfalfa still in the field. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

Lewis Lake Divide (09/06): 0.0" SWE, 0.0" snow depth.

At this point in early September, a reading of 0.0" SWE at Lewis Lake Divide is entirely normal — the historical median SWE for this date is also 0.0", so the station is at its expected seasonal condition. The relevant snowpack story for 2026 is one of timing: mountain snowpack across the upper Snake River basin melted out approximately 4–6 weeks ahead of the historical median meltout date, driven by an anomalous March heat wave. That early meltout accelerated spring runoff and compressed the recharge window for Lake Walcott and upstream reservoirs. Snowpack is no longer a supply variable for the remainder of the 2026 irrigation season — the water that was going to arrive from snowmelt has already arrived.

Streamflow Conditions

Snake River near Minidoka at Howells Ferry (USGS 13081500): 6,970 cfs, stable (09/07).

The Howells Ferry gauge is Minidoka County's primary upstream supply signal — it measures what the Snake River is delivering before any Magic Valley diversions occur downstream at Milner. At 6,970 cfs and holding stable, the river is in a late-season baseflow regime consistent with a season that peaked early and has been drawing down since spring. This gauge drains approximately 15,700 square miles of upper Snake River watershed, meaning its readings reflect integrated conditions from Palisades Reservoir, American Falls Reservoir, and all Snake River tributaries upstream of Minidoka Dam. A stable reading at this stage of September indicates no significant runoff event is contributing and flows are driven by managed releases and aquifer return flows. Irrigators and Minidoka Irrigation District staff should note that flows at Howells Ferry are a leading indicator for conditions that will appear downstream at Milner Dam — changes here will be visible to Twin Falls, Jerome, and Cassia county users weeks later.

Seasonal Guidance

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Data Sources: SNOTEL data through September 6, 2026; USGS streamflow data through September 7, 2026.

Data Current As Of: September 7, 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 Minidoka Irrigation District (primary delivery entity receiving water from Minidoka Dam diversions), U.S. Bureau of Reclamation Pacific Northwest Region, Boise office (operates Minidoka Dam and Lake Walcott as part of the USBR Minidoka Project; also manages American Falls Reservoir and Palisades Reservoir upstream context), and Idaho Department of Water Resources (administers Water District 36, middle Snake River) for regulatory decisions and water rights administration.