Renwick Dam Lake
Pembina County, WisconsinEutrophic
Renwick Dam Lake is a 223-acre productive, nutrient-rich eutrophic lake in Pembina County, ND. Water quality is graded C based on 2 sampling years through 2025.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2025-10-22. Grade methodology: LakeGrade methodology.
Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Very murky, less than 3 ft of visibility. Chlorophyll-a: 3.5 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 3.5 µg/L | A |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 223 acres |
Location
County Ranking
Ranked #1 of 1 lakes in Pembina County
Cleaner Lakes Within 30 Miles
Renwick Dam Lake holds Grade C. 2 nearby lakes hold higher grades.
- BMt Carmel Dam LakeCavalier County · 25.5 mi · Higher grade (C → B)
- BHomme Dam LakeWalsh County · 25.6 mi · Higher grade (C → B)
Nearby Lakes in Pembina County
More Wisconsin Lake Rankings
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Renwick Dam Lake is a man-made reservoir impounded by the Renwick Dam (completed 1962), built primarily for flood risk reduction on the Tongue River; earth-type dam, 49 ft tall and 1,400 ft long.
- Surface area
- 223 ac
- Normal storage
- 1,478 ac-ft
- Max storage
- 11,658 ac-ft
- Drainage area
- 144 sq mi
- Hazard class
- High
- Owner
- Pembina County WRB
All listed purposes: Flood Risk Reduction;Recreation.
Source: USACE National Inventory of Dams, NID ID ND00054 · Operator website
EPA Impairment Status
Renwick 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-09020316-002-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: 3