Larimer County Water Intelligence Brief

August 31, 2026 | Free-Tier Edition

*Cache la Poudre & Big Thompson Corridor | C-BT System | Water Division 1*

Situation Summary

Both the Cache la Poudre and Big Thompson rivers are running at late-season low volumes this week, with the Poudre showing a modest rising signal at Fort Collins and Timnath while the Big Thompson at Loveland continues to fall — conditions that reflect the compressed supply window facing alfalfa, hay, corn, and livestock operations across the county's two river corridors. For C-BT allotment holders and canal company members, delivery reliability through September depends heavily on in-county storage status at Horsetooth Reservoir and Carter Lake, both of which have been drawing down through a full irrigation season following the anomalously early 2026 meltout. 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 end-of-summer conditions consistent with complete seasonal meltout. Stations are reporting as follows as of August 30, 2026:

Bear Lake, Hourglass Lake, and Joe Wright show trace SWE readings with zero snow depth — likely instrument artifacts rather than meaningful snowpack. No station reports measurable snow on the ground. Because no percent-of-median figures are reported for this date, the median SWE for late August is also effectively 0.0" — these stations are at their normal seasonal condition for this point in the calendar, not anomalously below normal today.

The relevant 2026 snowpack story is one of timing, not current condition: across both the Big Thompson headwaters (Willow Park, Bear Lake) and the Cache la Poudre headwaters (Joe Wright, Deadman Hill, Hourglass Lake), snowpack melted out approximately 4–6 weeks ahead of the historical median meltout date, driven by the anomalous March heat event. That early meltout accelerated spring runoff, reduced the duration of snowmelt contribution to streamflow, and compressed the effective delivery season — the downstream consequences of which are now reflected in current river conditions.

Streamflow Conditions

Big Thompson River at Loveland (USGS 06741510): 46 cfs, falling, as of August 31. This gauge captures combined native Big Thompson flow and any C-BT releases moving through the Olympus Dam reach into the Loveland agricultural corridor. A falling trend at this stage of the season indicates declining supply availability for Big Thompson irrigators. At 46 cfs, flows are at a level where junior priority holders should be monitoring delivery status closely.

Cache la Poudre River at Fort Collins (USGS 06752260): 23 cfs, rising, as of August 31. This is an in-county gauge on Colorado's only federally designated Wild and Scenic River. The rising signal at Fort Collins may partly reflect Fort Collins municipal return flows augmenting the lower Poudre — a characteristic feature of the urban-agricultural interface at this reach. At 23 cfs, agricultural supply on the lower Poudre remains constrained.

Cache la Poudre River above Boxelder Creek near Timnath (USGS 06752280): 19 cfs, rising, as of August 31. This downstream Larimer County gauge confirms the rising trend observed at Fort Collins, with flows moving through the lower Poudre corridor toward the Larimer-Weld county line. The modest rising signal at both Poudre gauges warrants monitoring but does not indicate a significant supply improvement at current levels.

Across both river systems, flows are at late-season lows consistent with post-meltout base flow conditions. The divergence between a falling Big Thompson and a modestly rising Poudre reflects the different supply dynamics of the two corridors: the Big Thompson's C-BT-augmented system and the Poudre's mixed native-flow and return-flow character.

Seasonal Guidance

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

Data Current As Of: August 31, 2026. Streamflow and snowpack data sourced from NRCS SNOTEL network and 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 Northern Colorado Water Conservancy District (Northern Water — headquartered in Berthoud, Larimer County; C-BT Project administrator; Horsetooth Reservoir and Carter Lake storage data via northernwater.org or USBR HydroMet site HRT), City of Fort Collins Utilities, Colorado Division of Water Resources Water Division 1 (Greeley office), and your local canal company for regulatory decisions, delivery scheduling, and water rights administration. This brief does not constitute legal or water rights advice.