Larimer County Water Intelligence Brief

September 14, 2026 | Free-Tier Edition

Situation Summary

Both the Cache la Poudre and Big Thompson rivers are running at low late-season flows, with the Poudre showing a modest rising signal and the Big Thompson declining at Loveland — conditions that define the operational reality for irrigators across the county this week. C-BT allotment holders and canal company members should anticipate tightening late-season supply as the two-river system transitions fully into post-irrigation-season mode. 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 at or near zero snow water equivalent as of September 13, consistent with normal seasonal conditions at this point in the calendar — no percent-of-median comparisons apply because the historical median SWE for mid-September is itself zero at these elevations. The meaningful 2026 snowpack story is timing: stations melted out 4–6 weeks ahead of the historical median meltout date, driven by an anomalous March heat wave.

Big Thompson headwaters (Rocky Mountain National Park corridor):

Cache la Poudre headwaters:

Bear Lake's 1.0" snow depth with 0.0" SWE likely reflects trace early-season surface frost or light accumulation without measurable water content — not meaningful snowpack. Joe Wright's 0.2" SWE is the only station showing any measurable water, a negligible figure at this date. No snowmelt contribution to streamflow should be anticipated from any of these stations in the near term.

Streamflow Conditions

The two-river system is running at low late-season volumes, with divergent directional signals between the Poudre and Big Thompson corridors.

Big Thompson River:

At 39 cfs and falling, the Big Thompson is delivering minimal flow through the Loveland agricultural reach. This gauge captures combined native Big Thompson flow plus any C-BT releases from the Olympus Dam system — the falling trend indicates declining total delivery through this corridor.

Cache la Poudre River:

Both in-county Poudre gauges are rising modestly. The Fort Collins gauge reflects combined upstream inflow and municipal return flows from City of Fort Collins Utilities — Fort Collins urban return flows are a meaningful component of lower Poudre supply at this time of year, and the rising signal at both stations may partly reflect that dynamic rather than natural inflow increases alone. The 2 cfs difference between Fort Collins (12 cfs) and Timnath (10 cfs) is within normal measurement variability at these low flows. Poudre irrigators should not interpret the rising signal as indicating improved supply outlook — volumes remain very low for late-season agricultural use.

Seasonal Guidance

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Data Sources: SNOTEL data through September 13, 2026; USGS streamflow data through September 14, 2026

Data Current As Of: September 14, 2026 | 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.