Upper Grizzly Lake
La Plata County, ColoradoView mapDirections
Colorado WQCD publishes the water-quality measurements for Upper Grizzly Lake. Here is what has been measured.
- Limited data
Upper Grizzly Lake in La Plata County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Phosphorus: 6.5 µg/L.
Upper Grizzly Lake is a lake in La Plata County, Colorado.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2020-09-23. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Upper Grizzly Lake is safe to swim in today is a call for the Water Quality Control Division of the Colorado Department of Public Health and Environment and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Upper Grizzly Lake
These are the measurements Colorado WQCD publishes for Upper Grizzly Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 6.5 µg/L. TSI 31.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 6.5µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 31 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
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Frequently asked questions about Upper Grizzly Lake
Where is Upper Grizzly Lake?
- Upper Grizzly Lake is a lake in La Plata County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Upper Grizzly Lake?
- Upper Grizzly Lake in La Plata County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Phosphorus: 6.5 µg/L.
Is Upper Grizzly Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
2 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Colorado Water Science Center
USGS-CO2 samples · 2020
Analytical methods
- P, wu, WCA, persulfate CF color
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.