Sevier County Water Intelligence Brief

August 17, 2026 | Sevier River Basin

Situation Summary

The Sevier River Basin is operating in a late-summer low-flow environment, with snowpack fully melted and streamflows on a general declining seasonal trajectory. The 2026 season was defined by an anomalous March heat wave that drove snowmelt 4–6 weeks ahead of the historical median meltout date, compressing the runoff window and reducing recharge to late-season baseflows. Reservoir storage data and 7-day forecast details are available in the full brief.

Snowpack Conditions

Farnsworth Lake SNOTEL Station (reading through August 16, 2026):

Snow water equivalent (SWE) is currently 0.2 inches, with a snow depth of 0.0 inches.

This combination — a trace SWE reading alongside zero measured snow depth — reflects an instrument condition typical of late summer, where residual moisture registers in the sensor without meaningful snowpack present on the ground. For practical planning purposes, the basin should be considered fully melted out. No percent-of-median figure is reported for this date, which is consistent with the historical median SWE for mid-August also being 0.0 inches — this station is at its normal seasonal condition for this point in the calendar.

The meaningful snowpack signal for 2026 is not today's reading but the season's meltout timing: Farnsworth Lake and other Mountain West stations melted out 4–6 weeks ahead of the historical median meltout date, driven by the anomalous March heat event. That early meltout concentrated spring runoff into a shorter window and reduced the duration of late-season streamflow support that irrigators typically rely on through July and August. With snowpack no longer a supply variable, current and near-term agricultural water availability is governed entirely by streamflow conditions and stored reservoir water.

Streamflow Conditions

Five USGS gauges provide coverage across the Sevier River Basin. Conditions are mixed by location, with the upper basin showing falling flows and the middle reach showing a modest rise.

Sevier River at Hatch, UT (upper basin): 44 cfs, falling as of August 17. This is the uppermost mainstem gauge and reflects runoff and baseflow conditions from the headwaters area. A falling trend at this point in the season is consistent with normal late-summer recession, but the rate of decline warrants monitoring for downstream delivery implications.

Sevier River near Kingston, UT (upper-middle basin): 10 cfs, rising as of August 17. The rising signal at Kingston, against the falling trend at Hatch, may reflect tributary contributions or local inflow between the two gauges. At 10 cfs, the absolute flow volume is low. Users in this reach should monitor closely, as this rising signal may be short-lived in the absence of meaningful precipitation.

Sevier River near Lynndyl, UT (lower basin): 75 cfs, falling as of August 17. This is the highest absolute flow reading in the network and reflects the cumulative drainage of the basin above Lynndyl, including reservoir releases and tributary inputs. The falling trend is notable given this is a critical delivery point for lower-basin irrigators. Continued decline through August could compress available supply for late-season irrigation needs.

Sevier River near Sigurd, UT (middle basin): No recent flow data available as of the report date. The absence of current data at this gauge represents an information gap for users in the Sigurd area and central Sevier County. Until data resumes, users should not assume conditions at this gauge are consistent with either adjacent reading.

Manti Creek below Dugway Creek, near Manti, UT (tributary, Sanpete County border area): 4 cfs, stable as of August 16. Manti Creek is a tributary input to the broader basin system. Stable flow at 4 cfs indicates this stream is in steady late-summer baseflow mode without significant change.

Across the network, the overall picture is a basin in seasonal recession, with upper-basin flows falling, a mid-basin data gap, and lower-basin flows still running but on a downward trajectory. Late-season water availability in the Sevier Valley depends heavily on how quickly the Lynndyl flow continues to decline and on what reservoir releases are sustaining the lower-basin reading.

Seasonal Guidance

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Data Sources: SNOTEL data through August 16, 2026; USGS streamflow data through August 17, 2026

Data Current As Of: August 17, 2026 | Utah Division of Water Rights

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, Utah Division of Water Resources, and the Utah State Engineer's Office for regulatory decisions and water rights administration.