Stolley Pit Lake
Clay County, IowaView mapDirections
Iowa DNR publishes the water-quality measurements for Stolley Pit Lake. Here is what has been measured.
- Eutrophic
- Public access
Stolley Pit Lake in Clay County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.7 ft visibility. Phosphorus: 48 µg/L. Chlorophyll-a (algae): 17.3 µg/L.
Free interactive depth-contour map of Stolley Pit Lake, reaching a maximum surveyed depth of 12 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
Stolley Pit Lake is a productive, nutrient-rich eutrophic lake in Clay County, Iowa. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-09. Methodology: how these readings are compared.
Swimming conditions
Readings onlyAlgae risk
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Stolley Pit Lake is safe to swim in today is a call for the Iowa Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Stolley Pit Lake
These are the measurements Iowa DNR publishes for Stolley Pit Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.7 ft of visibility. Phosphorus 48 µg/L. Chlorophyll-a 17.3 µg/L. TSI 60.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 48µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 17.3µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Fishing Stolley Pit Lake
Water quality readings over time
2 seasons of samples on record (2023–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Phosphorus
Worsening+13.5 µg/L/yr2 years
Chlorophyll-a
Improving-9.1 µg/L/yr2 years
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Stolley Pit Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.
- Spencer, City Of StpSpencer · 3.6 mi away · NPDES IA0021059MajorRecent violation
- Corn Belt Power Cooperative-Wisdom StationSpencer · 3.4 mi away · NPDES IA0004570Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Clay County
Frequently asked questions about Stolley Pit Lake
Where is Stolley Pit Lake?
- Stolley Pit Lake is a lake in Clay County, Iowa. Its water-quality measurements are published by Iowa DNR and shown on this page as reported.
What is the water quality of Stolley Pit Lake?
- Stolley Pit Lake in Clay County, Iowa has water-quality measurements published by Iowa DNR, shown here as reported. Water clarity: 2.7 ft visibility. Phosphorus: 48 µg/L. Chlorophyll-a (algae): 17.3 µg/L.
Is Stolley Pit Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Stolley Pit Lake?
- Public access to Stolley Pit Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Iowa's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
29 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX29 samples · 2023–2024
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- In-Vitro Determination of Chlorophyll
- ISU modification of APHA 2130-B
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)