Gunnison Reservoir
Sanpete County, UtahView mapDirections
Utah DWQ publishes the water-quality measurements for Gunnison Reservoir. Here is what has been measured.
- Eutrophic
- 75 ft max depth
- Limited data
Gunnison Reservoir in Sanpete County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 0.8 ft visibility. Phosphorus: 113.5 µg/L. Chlorophyll-a (algae): 8.2 µg/L.
Gunnison Reservoir is a productive, nutrient-rich eutrophic lake in Sanpete County, Utah with an estimated average depth of about 75 feet. Compared to the 10 other monitored lakes in Sanpete County, Gunnison Reservoir ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2020-08-04. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Gunnison Reservoir is safe to swim in today is a call for the Utah Division of Water Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Gunnison Reservoir
These are the measurements Utah DWQ publishes for Gunnison Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 0.8 ft of visibility. Phosphorus 113.5 µg/L. Chlorophyll-a 8.2 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 114µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 8.2µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 68 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Gunnison Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~75 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Utah has not published bathymetry for Gunnison Reservoir.
Lake Size & Watershed
Watershed (drainage) area
734 sq mi
HydroLAKES / HydroSHEDS
Surface area
1,287 acres
HydroLAKES / HydroSHEDS
Shoreline
9.3 mi
HydroLAKES / HydroSHEDS
Elevation
5,394 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
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Fishing Gunnison Reservoir
Reservoir Info (USACE NID)
Gunnison Reservoir is a man-made reservoir impounded by the Gunnison (completed 1889), built primarily for irrigation on the San Pitch River; earth-type dam, 42 ft tall and 1,240 ft long.
- Normal storage
- 12,800 ac-ft
- Max storage
- 33,000 ac-ft
- Drainage area
- 670 sq mi
- Hazard class
- High
- Owner
- GUNNISON IRRIGATION COMPANY
Source: USACE National Inventory of Dams, NID ID UT00130 · Operator website
Nearby Lakes in Sanpete County
Frequently asked questions about Gunnison Reservoir
Where is Gunnison Reservoir?
- Gunnison Reservoir is a lake in Sanpete County, Utah. Its water-quality measurements are published by Utah DWQ and shown on this page as reported.
What is the water quality of Gunnison Reservoir?
- Gunnison Reservoir in Sanpete County, Utah has water-quality measurements published by Utah DWQ, shown here as reported. Water clarity: 0.8 ft visibility. Phosphorus: 113.5 µg/L. Chlorophyll-a (algae): 8.2 µg/L.
Is Gunnison Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Gunnison Reservoir?
- No published bathymetric survey covers Gunnison Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 75 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Gunnison Reservoir across LakeQuality
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Where this data comes from
10 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX10 samples · 2020
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)