Water Intelligence Brief

Twin Falls County, ID — Snake River Basin (Magic Valley)

July 6, 2026 | Free-Tier Edition

Situation Summary

The 2026 irrigation season arrived under an early-melt condition across the upper Snake River basin, with SNOTEL stations melting out 4–6 weeks ahead of their historical median meltout dates — meaning the mountain snowpack that typically sustains late-summer canal deliveries has already been fully committed to streamflow. Current Snake River gauge readings at and below Milner Dam reflect active irrigation-season diversions by the Twin Falls Canal Company and Northside Canal Company, the two primary diverters serving Magic Valley's approximately 202,000 irrigated acres. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

All three SNOTEL stations reporting for the Twin Falls County region show snowpack is fully melted out as of July 5, 2026 — consistent with normal conditions for this point in the calendar year, as median SWE values are also 0.0" at this date.

The critical supply signal for 2026 is not today's SWE reading — it is meltout timing. Stations across the upper basin melted out 4–6 weeks ahead of their historical median meltout dates. Snowmelt-driven inflows that would historically extend into July have already passed downstream. Canal deliveries from this point forward depend on upstream reservoir storage releases and residual baseflow — not new snowmelt.

Streamflow Conditions

Two USGS gauges monitor Snake River conditions directly relevant to Magic Valley canal operations:

Together, these two readings confirm that the Milner diversion system is operating at full capacity capture. The upstream supply question — what American Falls Reservoir and Palisades Reservoir are releasing to sustain canal diversions through late season — is the critical variable that cannot be answered from gauge data alone.

Seasonal Guidance

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Data Sources: NRCS SNOTEL network data through July 5, 2026; USGS National Water Information System streamflow data through July 6, 2026.

Data Current As Of: July 6, 2026.

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, Idaho Department of Water Resources (IDWR — administers Water District 36, the middle Snake River priority system), Twin Falls Canal Company (primary south-bank diverter at Milner Dam), Northside Canal Company (primary north-bank diverter at Milner Dam), and U.S. Bureau of Reclamation, Pacific Northwest Region (Boise office — for American Falls Reservoir and Palisades Reservoir upstream storage context) for regulatory decisions and water rights administration.