N St Vrain Lake is a cold, clear oligotrophic lake in Boulder County, Colorado. Water quality is graded A based on 1 sampling years through 2024.
Source: EPA Water Quality Portal sampling records, Colorado DNR, last sampled 2024-10-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
No clarity data. Phosphorus level: 10.6 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 10.6 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
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Location
County Ranking
Ranked #1 of 1 lakes in Boulder County
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More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-10-29
Monitoring stations: 1