Charles Mill Reservoir
Ashland County, WisconsinLimited DataHypereutrophic
Charles Mill Reservoir is a 1,350-acre highly nutrient-loaded hypereutrophic lake in Ashland County, OH. Water quality is graded F based on 1 sampling years through 2021.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2021-10-11. 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 0.9 ft of visibility. Trophic State Index: 79.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 79 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1.4K acres |
Location
County Ranking
Ranked #1 of 1 lakes in Ashland County
Nearby Lakes in Ashland County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Reservoir Info (USACE NID)
Charles Mill Reservoir is a man-made reservoir impounded by the Charles Mill Dam (completed 1936), built primarily for flood risk reduction on the BLACK FORK OF MOHICAN RIVER; earth-type dam, 52 ft tall and 1,390 ft long.
- Surface area
- 1,350 ac
- Normal storage
- 7,400 ac-ft
- Max storage
- 88,000 ac-ft
- Drainage area
- 215 sq mi
- Hazard class
- High
- Owner
- USACE - Huntington District
All listed purposes: Flood Risk Reduction;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID OH00020 · Operator website
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2021-10-11
Monitoring stations: 3