Otter Creek Lake
Tama County, WisconsinEutrophic
Otter Creek Lake is a 60-acre productive, nutrient-rich eutrophic lake in Tama County, IA. Water quality is graded D based on 2 sampling years through 2021. Compared to the 2 other monitored lakes in Tama County, Otter Creek Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2021-08-04. 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 1.3 ft of visibility. Chlorophyll-a: 24 µg/L. Trophic State Index: 67.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 24 µg/L | D |
| Trophic State Index (TSI) | 67 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 60 acres |
Location
County Ranking
Ranked #1 of 3 lakes in Tama County
Cleaner Lakes Within 30 Miles
Otter Creek Lake holds Grade D. 2 nearby lakes hold higher grades.
- BSand LakeMarshall County · 17.8 mi · Two grade letters higher (D → B)
- CGreen Castle LakeMarshall County · 19.2 mi · Higher grade (D → C)
Nearby Lakes in Tama County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Otter Creek Lake is a man-made reservoir impounded by the Otter Creek Lake Dam (completed 1968), built primarily for recreation on the OTTER CREEK; earth-type dam, 45 ft tall and 935 ft long.
- Surface area
- 60 ac
- Normal storage
- 680 ac-ft
- Max storage
- 1,290 ac-ft
- Drainage area
- 1.74 sq mi
- Hazard class
- Significant
- Owner
- Tama County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA01032 · Operator website
EPA Impairment Status
Otter 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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 02-IOW-720 · 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: 2021-08-04
Monitoring stations: 1