L. Ste. Louise Lake
St. Charles County, WisconsinEutrophic
L. Ste. Louise Lake is a 70-acre productive, nutrient-rich eutrophic lake in St. Charles County, MO. Water quality is graded D based on 3 sampling years through 2024. Compared to the 10 other monitored lakes in St. Charles County, L. Ste. Louise Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-15. 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 2.6 ft of visibility. Phosphorus level: 40.8 µg/L. Chlorophyll-a: 18.3 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.6 ft | F |
| Phosphorus | 40.8 µg/L | C |
| Chlorophyll-a (Algae) | 18.3 µg/L | C |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 70 acres |
Location
County Ranking
Ranked #2 of 11 lakes in St. Charles County
Cleaner Lakes Within 30 Miles
L. Ste. Louise Lake holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in St. Charles 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)
L. Ste. Louise Lake is a man-made reservoir impounded by the Lake Sainte Louise Dam (completed 1967), built primarily for recreation on the BRANCH PERUQUE CREEK; earth-type dam, 52 ft tall and 790 ft long.
- Surface area
- 70 ac
- Normal storage
- 1,170 ac-ft
- Max storage
- 1,420 ac-ft
- Drainage area
- 1.04 sq mi
- Hazard class
- High
- Owner
- LAKE SAINT LOUIS COMM.
Source: USACE National Inventory of Dams, NID ID MO10490 · Operator website · Matched by proximity (0.83 km)
EPA Impairment Status
L. Ste. Louise 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_7055.00 · Official waterbody report · Matched by proximity (0.22 km)
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: 2024-09-15
Monitoring stations: 1