Larimer County Water Intelligence Brief

July 20, 2026 | Free-Tier Edition

Situation Summary

The 2026 irrigation season is operating under an accelerated hydrological calendar across Larimer County's two-river system — the Cache la Poudre and Big Thompson corridors both entered their post-snowmelt phase 4–6 weeks ahead of the historical median meltout date, shifting peak runoff and reservoir fill windows earlier than most operational plans anticipated. In-county C-BT storage at Horsetooth Reservoir and Carter Lake now carries the full weight of late-season supply for both C-BT allotment holders and direct-flow irrigators as native streamflows decline toward their summer base. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

All five SNOTEL stations monitoring Larimer County's headwaters are reporting conditions consistent with full seasonal meltout as of July 19, 2026.

Big Thompson Headwaters (Rocky Mountain National Park corridor):

Bear Lake and Willow Park are the primary snowpack indicators for the Big Thompson delivery corridor and the C-BT system's native basin contribution. Bear Lake shows a trace residual depth of 2.0" with zero SWE — consistent with end-of-season consolidated granular snow or ice rather than active snowpack. Willow Park shows the inverse: 1.0" SWE recorded against 0.0" reported depth, a likely instrumentation artifact at this point in the season rather than a meaningful supply signal. Neither station shows a percent-of-median figure, which indicates the historical median SWE for this date is also 0.0" — both stations are at their normal seasonal condition for mid-July. The meaningful signal for 2026 is timing: these stations melted out 4–6 weeks ahead of the historical median meltout date.

Cache la Poudre Headwaters:

Joe Wright retains a nominal 0.1" SWE with 5.0" of snow depth — the only station in the network still showing any measurable water equivalent. This is consistent with a high-elevation shaded site holding a remnant patch, not active snowpack contributing meaningful melt to Poudre streamflows. Deadman Hill and Hourglass Lake are fully melted out, with zero readings across all metrics. As with the Big Thompson stations, no percent-of-median figures are shown, meaning these readings are within normal range for this calendar date. The 2026 story on the Poudre headwaters, as on the Big Thompson, is the early meltout — not anomalously low snowpack today.

Integrated Snowpack Assessment: Across all five stations, Larimer County's headwaters are effectively snow-free. No meaningful snowmelt contribution to streamflow should be expected from either river system for the remainder of the season. Supply going forward is a function of in-county reservoir storage and residual baseflow.

Streamflow Conditions

Big Thompson River at Loveland (USGS 06741510): 70 cfs — Stable

The Loveland gauge captures combined native Big Thompson flow and any C-BT releases through the Olympus Dam reach. At 70 cfs and stable, the Big Thompson is delivering a functional late-season flow to the Loveland agricultural reach. This gauge is the primary operational indicator for Big Thompson corridor irrigators — alfalfa, hay, corn, and cattle operations between Loveland and the Larimer/Weld County line. Stable trending suggests no immediate disruption, but with snowmelt exhausted, this flow is sustained by reservoir operations and residual baseflow rather than ongoing runoff.

Cache la Poudre River at Fort Collins (USGS 06752260): 33 cfs — Rising

The Fort Collins gauge is an in-county indicator for the upper Poudre agricultural reach and captures the combined effect of headwater baseflow, municipal diversions, and Fort Collins Utilities return flows. At 33 cfs and rising, the Poudre at Fort Collins is showing a modest uptick — likely reflecting reduced upstream agricultural diversions in the rotation cycle, municipal return flow contributions, or both, rather than new snowmelt input. This gauge sits within Larimer County; the rising trend is a near-term positive signal for downstream users but should not be read as a supply recovery.

Cache la Poudre River above Boxelder Creek near Timnath (USGS 06752280): 6 cfs — Rising

The Timnath gauge reflects Poudre flows at the Larimer/Weld County line after the full weight of upstream agricultural diversions and Fort Collins municipal withdrawals have reduced the river substantially. At 6 cfs and rising, this gauge is indicating very low but incrementally improving flow at the county boundary. The rising trend parallels the Fort Collins gauge signal. Poudre irrigators holding junior priorities in the lower Larimer County reach should treat this reading as a baseline for current availability — conditions here remain tight.

Seasonal Guidance

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Data Sources: SNOTEL data through July 19, 2026; USGS streamflow data through July 20, 2026

Data Current As Of: Colorado Division of Water Resources

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, Northern Colorado Water Conservancy District (Northern Water — headquartered in Berthoud, Larimer County; administers C-BT Project; Horsetooth Reservoir and Carter Lake data via northernwater.org or USBR HydroMet site HRT), City of Fort Collins Utilities (municipal Poudre diversions), and Colorado Division of Water Resources Water Division 1 (Greeley office) for regulatory decisions and water rights administration.