Cassia County Agricultural Water Intelligence Brief

August 31, 2026 | Free-Tier Edition

Situation Summary

Late-season streamflow in both of Cassia County's agricultural zones is running at minimal levels, with Cassia Creek below Blacksmith Creek at 4 cfs (falling) and the Raft River above Onemile Creek near Malta at 3 cfs (rising) — conditions consistent with the tail end of a compressed irrigation season following an early-meltout year. For Snake River corridor irrigators, Burley Irrigation District delivery reliability now depends entirely on upstream storage and Snake River mainstem flows — no active in-county Snake River gauge exists within Cassia County boundaries, so supply assessment for the Burley service area relies on upstream Milner and Twin Falls reference points. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

All three SNOTEL stations reporting for Cassia County's contributing terrain show zero snow water equivalent and zero snow depth as of August 30 — Bostetter R.S., Howell Canyon, and Lewis Lake Divide each read 0.0" SWE and 0.0" depth. This is the normal seasonal condition for this date; median SWE for late August is also 0.0" at all three stations, so no below-normal signal is present in current readings. The relevant 2026 snowpack story is timing: these stations melted out approximately 4–6 weeks ahead of the historical median meltout date, compressing the spring runoff pulse and accelerating the transition to late-season supply dependence. Snowpack is no longer a variable — upstream reservoir storage and Snake River mainstem flows are now the sole supply buffer for the Snake River corridor.

Streamflow Conditions

Snake River Corridor — Cassia Creek below Blacksmith Creek (USGS, 08/31): 4 cfs, falling. Cassia Creek is a minor tributary indicator for the broader north-county drainage — at 4 cfs and falling, it reflects typical late-August low-flow conditions with no meaningful delivery contribution to the irrigation system. This gauge signals where the local tributary system stands, not Snake River canal supply.

Raft River Valley — Raft River above Onemile Creek near Malta (USGS 13078000, 08/31): 3 cfs, rising. The rising trend is a notable signal for Raft River Valley ranchers and irrigators — at 3 cfs total, absolute supply remains very limited, but any late-season upward movement warrants attention. At this flow level, the Raft River supports only minimal direct diversion; livestock watering and modest hay irrigation are the primary uses at this scale. Ranchers should monitor whether the rising trend holds or reverses through the first week of September.

No active USGS Snake River gauge exists within Cassia County boundaries. The Snake River near Burley (USGS 13085045) is discontinued. Supply assessment for the Burley Irrigation District service area depends on upstream gauges at Milner and near Twin Falls — Burley Irrigation District and IDWR Water District 36 (Burley office) are the authoritative contacts for current delivery status.

Seasonal Guidance

Subscribe for the full brief including reservoir storage, weather forecasts, depletion analysis, and detailed operational recommendations.

Data Sources: SNOTEL data through August 30, 2026; USGS streamflow data through August 31, 2026.

Data Current As Of: August 31, 2026. SNOTEL data via NRCS National Water and Climate Center; streamflow data via USGS National Water Information System.

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; Burley district office, (208) 678-1019), Burley Irrigation District (primary delivery infrastructure for the Snake River corridor in Cassia County), and U.S. Bureau of Reclamation, Pacific Northwest Region (Boise office) for American Falls Reservoir and Palisades Reservoir upstream context and for regulatory decisions and water rights administration.