South Prairie Lake
Black Hawk County, WisconsinHypereutrophic
South Prairie Lake is a highly nutrient-loaded hypereutrophic lake in Black Hawk County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 6 other monitored lakes in Black Hawk County, South Prairie Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-10-23. Grade methodology: LakeGrade methodology.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 1.6 ft of visibility. Chlorophyll-a: 66.9 µg/L. Trophic State Index: 71.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 66.9 µg/L | F |
| Trophic State Index (TSI) | 71 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Location
County Ranking
Ranked #6 of 7 lakes in Black Hawk County
Cleaner Lakes Within 30 Miles
South Prairie Lake holds Grade F. 3 nearby lakes hold higher grades.
- DMitchell LakeBlack Hawk County · 7.4 mi · Higher grade (F → D)
- DGreen Belt LakeBlack Hawk County · 3.6 mi · Higher grade (F → D)
- DFisher LakeBlack Hawk County · 4.7 mi · Higher grade (F → D)
Nearby Lakes in Black Hawk County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Hypereutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
South Prairie Lake is a man-made reservoir impounded by the Viking Road Detention Dam (completed 1994), built primarily for flood risk reduction on the DRY CREEK; earth-type dam, 22 ft tall and 1,000 ft long.
- Normal storage
- 0 ac-ft
- Max storage
- 1,000 ac-ft
- Drainage area
- 6 sq mi
- Hazard class
- High
- Owner
- City of Cedar Falls
All listed purposes: Flood Risk Reduction;Other.
Source: USACE National Inventory of Dams, NID ID IA03104 · Operator website · Matched by proximity (0.7 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-10-23
Monitoring stations: 1