Larimer County Water Intelligence Brief

August 24, 2026 | Free-Tier Edition

Situation Summary

Larimer County's two-river system — the Cache la Poudre and Big Thompson — is operating under late-summer low-flow conditions following an anomalous 2026 season in which high-elevation snowpack melted out 4–6 weeks ahead of historical median meltout dates across all five headwater SNOTEL stations. In-county storage at Horsetooth Reservoir and Carter Lake, both C-BT Project facilities physically located in Larimer County and administered by Northern Water, are the primary operational buffer for C-BT allotment holders and canal company members as native streamflow declines toward its seasonal minimum. 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 normal late-August seasonal status — median snow water equivalent (SWE) for this calendar date at all stations is 0.0", and current readings confirm no residual snowpack remains.

Big Thompson headwaters (Rocky Mountain National Park corridor):

Cache la Poudre headwaters:

The key signal for 2026 is not today's SWE readings — which are at or near their normal seasonal baseline — but rather the timing of meltout, which occurred 4–6 weeks earlier than the historical median across both headwater systems. That early meltout accelerated peak runoff into late spring, compressing the window during which Poudre and Big Thompson irrigators could capture native flows. The small residual readings at Bear Lake and Joe Wright are trace amounts within normal late-season variability and do not represent a meaningful water supply.

Streamflow Conditions

Both the Cache la Poudre and Big Thompson systems are showing falling late-summer flows at all three active USGS gauges in or near Larimer County.

Big Thompson corridor:

The Loveland gauge captures combined native Big Thompson flow plus any C-BT releases through the Olympus Dam system. At 68 cfs and falling, the agricultural reach below Loveland is in its characteristic late-season low-flow period. Irrigators drawing from this reach should monitor daily for continued decline.

Cache la Poudre corridor:

The Poudre is running at very low late-season levels at both the Fort Collins and Timnath gauges — both of which are in-county stations. The Fort Collins reading reflects native Poudre flow after municipal diversions by City of Fort Collins Utilities; Fort Collins municipal return flows contribute to the incremental recovery visible between the Fort Collins gauge (5 cfs) and the downstream Timnath gauge (9 cfs), illustrating the urban-agricultural interface that characterizes the lower Poudre. The Poudre's Wild and Scenic River designation prohibits new dams or major diversions within the designated corridor, making existing senior water rights and C-BT storage the operational foundation for late-season supply management. Senior rights on the Poudre date to the 1860s–1870s; under current low-flow conditions, junior priority holders should be attentive to Water Division 1 administration.

Seasonal Guidance

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Data Sources: SNOTEL data through August 23, 2026; USGS streamflow data through August 24, 2026

Data Current As Of: August 24, 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, 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.