John Flannagan Reservoir@ Dam is a cold, clear oligotrophic lake in Dickenson County, Virginia. Water quality is graded A based on 2 sampling years through 2026. Compared to the 3 other monitored lakes in Dickenson County, John Flannagan Reservoir@ Dam ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Virginia DNR, last sampled 2026-06-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 17.1 ft down. Phosphorus level: 10 µg/L. Chlorophyll-a: 1.5 µg/L. Trophic State Index: 36.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.1 ft | A |
| Phosphorus | 10 µg/L | A |
| Chlorophyll-a (Algae) | 1.5 µg/L | A |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near John Flannagan Reservoir@ Dam
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Fishing John Flannagan Reservoir@ Dam
Location
County Ranking
Ranked #1 of 4 lakes in Dickenson County
Nearby Lakes in Dickenson County
Explore John Flannagan Reservoir@ Dam across LakeGrade
More Virginia Lake Rankings
Other Grade A Lakes in Virginia
Oligotrophic Lakes in Virginia
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: 2026-06-24
Monitoring stations: 1