Little River Lake
Decatur County, WisconsinEutrophic
Little River Lake is a 787-acre productive, nutrient-rich eutrophic lake in Decatur County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 2 other monitored lakes in Decatur County, Little River Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-30. 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 2.3 ft of visibility. Chlorophyll-a: 70 µg/L. Trophic State Index: 69.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 70 µg/L | F |
| Trophic State Index (TSI) | 69 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 787 acres |
Location
County Ranking
Ranked #3 of 3 lakes in Decatur County
Cleaner Lakes Within 30 Miles
Little River Lake holds Grade F. 4 nearby lakes hold higher grades.
- ANine Eagles LakeDecatur County · 10.6 mi · Two grade letters higher (F → A)
- BSlipbluff LakeDecatur County · 7.7 mi · Two grade letters higher (F → B)
- DBob White LakeWayne County · 19.9 mi · Higher grade (F → D)
- DWest Lake OsceolaClarke County · 20.1 mi · Higher grade (F → D)
Nearby Lakes in Decatur County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Little River Lake is a man-made reservoir impounded by the Little River Watershed Site M-1 (completed 1984), built primarily for flood risk reduction on the LITTLE RIVER; earth-type dam, 61 ft tall and 1,810 ft long.
- Surface area
- 787 ac
- Normal storage
- 10,869 ac-ft
- Max storage
- 32,650 ac-ft
- Drainage area
- 20.85 sq mi
- Hazard class
- High
- Owner
- Decatur County SWCD
All listed purposes: Flood Risk Reduction;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID IA02263 · Operator website · Matched by proximity (0.25 km)
EPA Impairment Status
Little River Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 05-GRA-1358 · Official waterbody report · Matched by proximity (2.91 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: 2024-09-30
Monitoring stations: 1