Stephens County, Oklahoma · Water Quality Report Card
Duncan Lake
Duncan Lake in Stephens County, Oklahoma is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.1 ft visibility.
- Clarity
- 4.1 ft
- Mean depth
- ~12 ft est.
- Type
- Eutrophic
Duncan Lake is a productive, nutrient-rich eutrophic lake in Stephens County, Oklahoma with an estimated average depth of about 12 feet.
Source: EPA Water Quality Portal sampling records, ODEQ, last sampled 2019-07-08. 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
Murky, only visible to about 4.1 ft. Trophic State Index: 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.1 ft | |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~12 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Oklahoma has not published bathymetry for Duncan Lake.
Where to stay near Duncan Lake
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Fishing Duncan Lake
Location
Nearby Lakes in Stephens County
Explore Duncan Lake across LakeGrade
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Other Lakes in Oklahoma
Eutrophic Lakes in Oklahoma
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
12 measurements from 3 monitoring stations, 2018–2019. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- OWRB Lakes Monitoring
OKWRB-LAKES_WQX12 samples · 2018–2019
Analytical methods
- OWRB Lakes Field Data Collection
Monitoring station identifiers (3)
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: 2019-07-08
Monitoring stations: 3