The Big Thompson River watershed drains approximately 305 square miles above the canyon mouth west of Loveland. In an average year, the Big Thompson River watershed produces approximately 133,000 acre feet of water. Nearly 75 percent of the production (99,000 acre feet) occurs during the peak snowmelt months of April through July.
The Big Thompson River watershed provides water to the cities of Berthoud, Johnstown and Loveland, and numerous ditch and reservoir companies in southeastern Larimer and western Weld counties.
Northern Water's SnoWatch system displays year-to-date snow accumulation for three SNOTELs in and near the Big Thompson River watershed. Bear Lake and Willow Park are both within the watershed and represent middle-elevation and high-elevation snow accumulation, respectively.
Colorado Division of Water Resources Website Link:
Lake Irene is situated west of the Continental Divide. Despite its location in the Upper Colorado River watershed, the Lake Irene SNOTEL is indicative of snow accumulation in the western portion of the Big Thompson River watershed.
Big Thompson River at mouth canyon near Drake
NRCS Snowpack Telemetry (SNOTEL) Website links: