Catamount Lake Top
Routt County, ColoradoView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- Limited data
Catamount Lake Top in Routt County, Colorado is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 46 µg/L.
- Trend
- ↓ Declining
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Watch Catamount Lake Top’s letter
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Why Catamount Lake Top has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Catamount Lake Top, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded phosphorus, but not water clarity and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by CDPHE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Catamount Lake Top is a lake in Routt County, Colorado. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2020-08-18. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Catamount Lake Top is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Water quality measurements for Catamount Lake Top
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Phosphorus 46 µg/L. TSI 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 46 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Fishing Catamount Lake Top
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +26.5 µg/L/yr | 2 |
EPA Impairment Status
Catamount Lake Top is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit COUCYA22_B · Official waterbody report · Matched by proximity (0.03 km)
Graded lakes near Catamount Lake Top
Catamount Lake Top has no grade, but these lakes within a short drive do.
Nearby Lakes in Routt County
Frequently asked questions about Catamount Lake Top
Where is Catamount Lake Top?
- Catamount Lake Top is a lake in Routt County, Colorado. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Catamount Lake Top?
- Catamount Lake Top in Routt County, Colorado is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 46 µg/L.
Is Catamount Lake Top safe to swim in?
- The letter is not a swimming clearance. Catamount Lake Top is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Explore Catamount Lake Top across LakeQuality
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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
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX2 samples · 2020
Analytical methods
- Phosphorus by Colorimetry
- Nitrogen in Water by Pyrolysis Detection
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database