Roberts Creek Lake
Marion County, WisconsinEutrophic
Roberts Creek Lake is a 296-acre productive, nutrient-rich eutrophic lake in Marion County, IA. Water quality is graded F based on 2 sampling years through 2024.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-17. 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 1.5 ft of visibility. Chlorophyll-a: 44.6 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 44.6 µg/L | F |
| Trophic State Index (TSI) | 70 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 296 acres |
Location
County Ranking
Ranked #1 of 1 lakes in Marion County
Cleaner Lakes Within 30 Miles
Roberts Creek Lake holds Grade F. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Marion County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Roberts Creek Lake is a man-made reservoir impounded by the Roberts Creek Dam (completed 1968), built primarily for recreation on the Roberts Creek; earth-type dam, 60 ft tall and 2,400 ft long.
- Surface area
- 296 ac
- Normal storage
- 3,043 ac-ft
- Max storage
- 21,863 ac-ft
- Drainage area
- 13.28 sq mi
- Hazard class
- Significant
- Owner
- Marion County Board of Supervisors
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID IA00655 · Operator website
EPA Impairment Status
Roberts Creek 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 04-LDM-1019 · 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: 2024-09-17
Monitoring stations: 1