Boysen Reservoir Transitional Embayment
Fremont County, WyomingView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
- Oligotrophic
- #6 of 18 in the county
Boysen Reservoir Transitional Embayment in Fremont County, Wyoming has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 10 µg/L.
- Clarity
- 11 ft
- Type
- Oligotrophic
- Phosphorus
- 10 µg/L
- Trend
- ↓ Declining
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Watch Boysen Reservoir Transitional Embayment’s letter
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Boysen Reservoir Transitional Embayment is a cold, clear oligotrophic lake in Fremont County, Wyoming. Water quality is graded B based on 1 sampling years through 2023. Overall water quality is declining over recent sampling years. Compared to the 17 other monitored lakes in Fremont County, Boysen Reservoir Transitional Embayment ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Wyoming DEQ, last sampled 2023-10-10. Grade methodology: LakeQuality methodology.
What Boysen Reservoir Transitional Embayment is good for
From access and monitoring records, not editorial picks.
- Clear water11 ft of visibility
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: B (Good)
Good clarity, visible to about 11 ft. Phosphorus 10 µg/L. TSI 40. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | Not graded |
| Phosphorus | 10 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 40 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Fishing Boysen Reservoir Transitional Embayment
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.39 m/yr | 4 |
| Phosphorus | ↓ Declining | +1.5 µg/L/yr | 4 |
County Ranking
Ranked #6 of 18 lakes in Fremont County
Nearby Lakes in Fremont County
Frequently asked questions about Boysen Reservoir Transitional Embayment
Where is Boysen Reservoir Transitional Embayment?
- Boysen Reservoir Transitional Embayment is a lake in Fremont County, Wyoming. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Boysen Reservoir Transitional Embayment?
- Boysen Reservoir Transitional Embayment in Fremont County, Wyoming has a water quality grade of B (Good). Water clarity: 11 ft visibility. Phosphorus: 10 µg/L.
Is Boysen Reservoir Transitional Embayment safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Boysen Reservoir Transitional Embayment across LakeQuality
2 thermal springs within 21.2 mi, nearest Wind River Canyon Spring
Species activity outlook by water temperature and season
Where to stay at Wyoming's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Wyoming's cleanest and most-polluted lakes, ranked
More Wyoming Lake Rankings
Other Grade B Lakes in Wyoming
Oligotrophic Lakes in Wyoming
Where this data comes from
48 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- State of Wyoming Department of Environmental Quality Watershed Program
WYDEQ_WATERSHED48 samples · 2020–2023
Analytical methods
- Secchi
- Total Phosphorus After Block Digestion
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.