Whitman Dam Lake
Nelson County, WisconsinLimited DataMesotrophic
Whitman Dam Lake is a 143-acre mesotrophic lake in Nelson County, ND. Water quality is graded B based on 1 sampling years through 2025. Compared to the 8 other monitored lakes in Nelson County, Whitman Dam Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2025-10-22. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 12 ft. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 143.4 acres |
Location
County Ranking
Ranked #1 of 9 lakes in Nelson County
Nearby Lakes in Nelson County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Whitman Dam Lake is a man-made reservoir impounded by the Whitman Dam (completed 1965), built primarily for flood risk reduction on the Middle Branch Forest River; earth-type dam, 49 ft tall and 1,200 ft long.
- Surface area
- 143.4 ac
- Normal storage
- 1,355.5 ac-ft
- Max storage
- 9,364 ac-ft
- Drainage area
- 84.7 sq mi
- Hazard class
- Significant
- Owner
- Walsh County WRB
All listed purposes: Flood Risk Reduction;Recreation.
Source: USACE National Inventory of Dams, NID ID ND00207 · Operator website
EPA Impairment Status
Whitman Dam Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit ND-09020308-002-L_00 · 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: 2025-10-22
Monitoring stations: 1