Natrona County, Wyoming · Water Quality Report Card
Pathfinder Reservoir
Pathfinder Reservoir in Natrona County, Wyoming is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 10 µg/L.
- Mean depth
- ~55 ft est.
- Type
- Oligotrophic
- Trend
- → Stable
Pathfinder Reservoir is a cold, clear oligotrophic lake in Natrona County, Wyoming with an estimated average depth of about 55 feet.
Source: EPA Water Quality Portal sampling records, Wyoming DEQ, last sampled 2015-09-23. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not rated for swimming — there is not enough monitoring data to judge this lake
Water Quality Grade: Not rated
No clarity data. Phosphorus level: 10 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 10 µg/L | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~55 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Wyoming has not published bathymetry for Pathfinder Reservoir.
Where to stay near Pathfinder Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Pathfinder Reservoir in Natrona County, Wyoming — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Fishing Pathfinder Reservoir
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | → Stable | +0.23 µg/L/yr | 5 |
Location
Nearby Lakes in Natrona County
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Oligotrophic Lakes in Wyoming
More records, surveys & data sources
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Where this data comes from
1 measurement from 1 monitoring station, 2015. 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_WATERSHED1 sample · 2015
Analytical methods
- Total Phosphorus After Block Digestion
Monitoring station identifiers (1)
Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2015-09-23
Monitoring stations: 1