Yenruogis Pond
Keokuk County, IowaView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
↑ up from B at the last regrade
- Mesotrophic
- #1 of 2 in the county
Yenruogis Pond in Keokuk County, Iowa has a water quality grade of A (Excellent). Water clarity: 9.9 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
- Clarity
- 9.9 ft
- Type
- Mesotrophic
- Trend
- ↑ Improving
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Watch Yenruogis Pond’s letter
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Yenruogis Pond is a mesotrophic lake in Keokuk County, Iowa. Water quality is graded A based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 1 other monitored lakes in Keokuk County, Yenruogis Pond ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-09-09. Grade methodology: LakeQuality methodology.
What Yenruogis Pond is good for
From access and monitoring records, not editorial picks.
- Clear water9.9 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 A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Good clarity, visible to about 9.9 ft. Phosphorus 21 µg/L. Chlorophyll-a 6.2 µg/L. TSI 47. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.9 ft | Not graded |
| Phosphorus | 21 µg/L | Good |
| Chlorophyll-a (Algae) | 6.2 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Fishing Yenruogis Pond
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.85 m/yr | 2 |
| Phosphorus | ↓ Declining | +4.5 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -7.8 µg/L/yr | 2 |
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Yenruogis Pond under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Sigourney City Of Stp (East)Sigourney · 3.2 mi away · NPDES IA0036595Recent 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.
County Ranking
Ranked #1 of 2 lakes in Keokuk County
Nearby Lakes in Keokuk County
Frequently asked questions about Yenruogis Pond
Where is Yenruogis Pond?
- Yenruogis Pond is a lake in Keokuk County, Iowa. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Yenruogis Pond?
- Yenruogis Pond in Keokuk County, Iowa has a water quality grade of A (Excellent). Water clarity: 9.9 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 6.2 µg/L.
Is Yenruogis Pond safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Explore Yenruogis Pond across LakeQuality
More Iowa Lake Rankings
Other Grade A Lakes in Iowa
Mesotrophic Lakes in Iowa
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)
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.
Other records on this page
Regulated discharger data from EPA ECHO (ICIS-NPDES)