White Oak Lake
Mahaska County, WisconsinHypereutrophic
White Oak Lake is a 20-acre highly nutrient-loaded hypereutrophic lake in Mahaska County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 2 other monitored lakes in Mahaska County, White Oak Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-08-28. 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 1.4 ft of visibility. Chlorophyll-a: 68.7 µg/L. Trophic State Index: 72.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.4 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 68.7 µg/L | F |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 20 acres |
Location
County Ranking
Ranked #2 of 3 lakes in Mahaska County
Cleaner Lakes Within 30 Miles
White Oak Lake holds Grade F. 2 nearby lakes hold higher grades.
- BYenruogis PondKeokuk County · 16 mi · Two grade letters higher (F → B)
- DHawthorn LakeMahaska County · 14 mi · Higher grade (F → D)
Nearby Lakes in Mahaska County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Hypereutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
White Oak Lake is a man-made reservoir impounded by the White Oak Lake Dam (completed 1983), built primarily for recreation on the TR- SNYDER CR.; earth-type dam, 39 ft tall and 555 ft long.
- Surface area
- 20 ac
- Normal storage
- 168 ac-ft
- Max storage
- 393 ac-ft
- Drainage area
- 0.94 sq mi
- Hazard class
- Significant
- Owner
- Mahaska County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA02274 · Operator website
EPA Impairment Status
White Oak 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 03-SSK-929 · Official waterbody report · Matched by proximity (0.3 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: 2024-08-28
Monitoring stations: 1