Fin And Feather Lake
Cerro Gordo County, Iowa16 acresView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · pH / acidity
- #4 of 4 in the county
Fin And Feather Lake in Cerro Gordo County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 2.3 ft visibility. Phosphorus: 112 µg/L. Chlorophyll-a (algae): 42 µg/L. Surface area: 16 acres.
- Clarity
- 2.3 ft
- Typical in August
- 78°F
- Area
- 16 acres
- Type
- Hypereutrophic
- Phosphorus
- 112 µg/L
- Chlorophyll-a
- 42 µg/L
- Trend
- ↓ Declining
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Stays near Fin And Feather Lake
Compare lakeside cabins, hotels, and vacation rentals near Fin And Feather Lake in Cerro Gordo County, Iowa — 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Fin And Feather Lake are listed below.
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Fin And Feather Lake is a 16-acre highly nutrient-loaded hypereutrophic lake in Cerro Gordo County, Iowa. Water quality is graded F based on 2 sampling years through 2022. Overall water quality is declining over recent sampling years. Compared to the 3 other monitored lakes in Cerro Gordo County, Fin And Feather Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2022-09-12. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyAlgae risk
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 F is nutrients and algae, not a swimming clearance. Fin And Feather Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pH / acidity. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 2.3 ft of visibility. Phosphorus 112 µg/L. Chlorophyll-a 42 µg/L. TSI 68. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 112 µg/L | Poor |
| Chlorophyll-a (Algae) | 42 µg/L | Poor |
| Trophic State Index (TSI) | 68 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Fin And Feather Lake typically sits around 78°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in Jun (about 72°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 9 field readings (2018–2022) via the EPA Water Quality Portal. See the full Fin And Feather Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 16 acres |
No bathymetric survey has been published for Fin And Feather Lake, so its depth is not documented here.
Fishing Fin And Feather Lake
Water Quality Trend: ↓ Declining
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.1 m/yr | 3 |
| Phosphorus | ↓ Declining | +7.95 µg/L/yr | 3 |
| Chlorophyll-a | ↓ Declining | +6.1 µg/L/yr | 3 |
Reservoir Info (USACE NID)
Fin And Feather Lake is a man-made reservoir impounded by the Lake Fin-Feather Dam (completed 1972), built primarily for recreation on the TR-WINNEBAGO RIVER; earth-type dam, 25 ft tall and 1,200 ft long.
- Surface area
- 16 ac
- Normal storage
- 76 ac-ft
- Max storage
- 123 ac-ft
- Drainage area
- 0.22 sq mi
- Hazard class
- Low
- Owner
- Cerro Gordo County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA00175 · Operator website · Matched by proximity (0.05 km)
EPA Impairment Status
Fin And Feather Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IA 02-WIN-840 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Fin And Feather Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Mason City, City Of StpMason City · 2.9 mi away · NPDES IA0057169MajorRecent violation
- Mason City, City Of WtpMason City · 3 mi away · NPDES IA0077305
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 #4 of 4 lakes in Cerro Gordo County
Nearby Lakes With Higher Grades
Fin And Feather Lake holds Grade F. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Cerro Gordo County
Frequently asked questions about Fin And Feather Lake
Where is Fin And Feather Lake?
- Fin And Feather Lake is a lake in Cerro Gordo County, Iowa. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Fin And Feather Lake?
- Fin And Feather Lake in Cerro Gordo County, Iowa has a water quality grade of F (Algae-prone). Water clarity: 2.3 ft visibility. Phosphorus: 112 µg/L. Chlorophyll-a (algae): 42 µg/L. Surface area: 16 acres.
Is Fin And Feather Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Fin And Feather Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pH / acidity. Check local advisories before you swim.
What is the water temperature of Fin And Feather Lake?
- Fin And Feather Lake typically sits around 78°F at the surface in August, from 9 EPA Water Quality Portal field readings (2018–2022). That is a typical value for the month, not a live reading.
Explore Fin And Feather Lake across LakeQuality
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
Where this data comes from
36 measurements from 1 monitoring station, 2020–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Iowa DNR Surface Water Monitoring Data
21IOWA_WQX36 samples · 2020–2022
Analytical methods
- Unknown
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)