Sunnen Lake
Washington County, WisconsinEutrophic
Sunnen Lake is a 198-acre productive, nutrient-rich eutrophic lake in Washington County, MO. Water quality is graded D based on 3 sampling years through 2023. Compared to the 1 other monitored lakes in Washington County, Sunnen Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2023-08-16. Grade methodology: LakeGrade methodology.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 1 ft of visibility. Phosphorus level: 61 µg/L. Chlorophyll-a: 14.3 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | F |
| Phosphorus | 61 µg/L | D |
| Chlorophyll-a (Algae) | 14.3 µg/L | C |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 198 acres |
Location
County Ranking
Ranked #2 of 2 lakes in Washington County
Cleaner Lakes Within 30 Miles
Sunnen Lake holds Grade D. 5 nearby lakes hold higher grades.
- ALake CapriSt. Francois County · 16.8 mi · Two grade letters higher (D → A)
- ACouncil Bluff LakeIron County · 15.4 mi · Two grade letters higher (D → A)
- ALake Shayne-Terre du Lac LakesWashington County · 16 mi · Two grade letters higher (D → A)
- ALake Marseilles-Terre du Lac LakesSt. Francois County · 17.1 mi · Two grade letters higher (D → A)
- ATimberline LakesSt. Francois County · 21.2 mi · Two grade letters higher (D → A)
Nearby Lakes in Washington County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
St. Louis city County · Clarity: 2.3 ft
Shelby County · Clarity: 3.2 ft
Macon County · Clarity: 1.8 ft
Harrison County · Clarity: 1.7 ft
Stone County · Clarity: 2.3 ft
Knox County · Clarity: 2.1 ft
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Sunnen Lake is a man-made reservoir impounded by the Sunnen Dam (completed 1948), built primarily for recreation on the FOURCHE A RENAULT; earth-type dam, 51 ft tall and 1,300 ft long.
- Surface area
- 198 ac
- Normal storage
- 2,540 ac-ft
- Max storage
- 5,000 ac-ft
- Drainage area
- 26.85 sq mi
- Hazard class
- High
- Owner
- YMCA of the Ozarks
Source: USACE National Inventory of Dams, NID ID MO30111 · Operator website
EPA Impairment Status
Sunnen Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MO_7294.00 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-08-16
Monitoring stations: 1