Twin Falls County Water Intelligence Brief

October 12, 2026 | Agricultural Water Management Edition

Situation Summary

Snake River flows at Milner Dam are reading 0 cfs as of October 12, consistent with end-of-irrigation-season diversion wind-down, while the Snake River near Twin Falls registers 545 cfs — reflecting return flows and spring contributions below the main diversion point. For Twin Falls County irrigators, this signals the close of the 2026 delivery season, with potato harvest operations now relying on stored soil moisture and any remaining field deliveries from Twin Falls Canal Company. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

All three SNOTEL stations in the Twin Falls County upstream supply shed are reporting at their normal seasonal condition for mid-October:

No percent-of-median figures are reported at any station, which is expected — median SWE for mid-October at these elevations is also at or near 0.0", meaning current readings reflect normal seasonal conditions for this date, not a deficit. As background context, the 2026 season was defined by an anomalous March heat wave that drove meltout 4–6 weeks ahead of the historical median meltout date across the upper Snake River supply shed — that early-melt signal shaped summer delivery conditions and is now a closed chapter of the season.

Streamflow Conditions

Two USGS gauges define the current Snake River picture for Twin Falls County:

The 0 cfs reading at Milner is the operational story: Twin Falls Canal Company and Northside Canal Company diversions have wound down, and the Snake River at Milner reflects end-of-season conditions. The 545 cfs registered downstream near Twin Falls represents the aggregated contribution of Snake River canyon springs, ESPA groundwater discharge, and return flows below the diversion — a reminder that the Snake River below Milner operates as a managed system where spring and aquifer contributions, not upstream runoff, define late and post-season flows.

Seasonal Guidance

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Data Sources: SNOTEL data through October 11, 2026; USGS streamflow data through October 12, 2026

Data Current As Of: October 12, 2026

Important Disclaimers: This brief provides automated analysis for informational purposes only. Specific numerical claims have not been independently verified. Consult official sources including Twin Falls Canal Company (primary south-bank diverter at Milner Dam), Northside Canal Company (north-bank diverter), Idaho Department of Water Resources (IDWR — Water District 36, middle Snake River priority system), and U.S. Bureau of Reclamation, Pacific Northwest Region (Boise office), for current operational status, water right administration, and upstream reservoir storage data. This brief does not constitute water rights or legal advice.