Manteno Lake
Shelby County, WisconsinEutrophic
Manteno Lake is a 4-acre productive, nutrient-rich eutrophic lake in Shelby County, IA. Water quality is graded D based on 2 sampling years through 2024. Compared to the 5 other monitored lakes in Shelby County, Manteno Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-03. 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 2.7 ft of visibility. Chlorophyll-a: 28.3 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.7 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 28.3 µg/L | D |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 4.4 acres |
Location
County Ranking
Ranked #1 of 6 lakes in Shelby County
Cleaner Lakes Within 30 Miles
Manteno Lake holds Grade D. 2 nearby lakes hold higher grades.
- CWillow LakeHarrison County · 17.5 mi · Higher grade (D → C)
- COldham LakeMonona County · 19.7 mi · Higher grade (D → C)
Nearby Lakes in Shelby County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Manteno Lake is a man-made reservoir impounded by the Mill Picayune Watershed Site M-24-10 (completed 1964), built primarily for fire protection, stock, or small fish pond on the MILL CREEK; earth-type dam, 36 ft tall and 787 ft long.
- Surface area
- 4.4 ac
- Normal storage
- 30 ac-ft
- Max storage
- 166 ac-ft
- Drainage area
- 3.8 sq mi
- Hazard class
- Low
- Owner
- Shelby County SWCD
All listed purposes: Fire Protection, Stock, Or Small Fish Pond;Flood Risk Reduction.
Source: USACE National Inventory of Dams, NID ID IA00992 · Operator website · Matched by proximity (0.06 km)
EPA Impairment Status
Manteno 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 06-BOY-1505 · Official waterbody report · Matched by proximity (0.28 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: 2024-09-03
Monitoring stations: 1