Lake Diane South Basin; Amboy Township
Hillsdale County, WisconsinEutrophic
Lake Diane South Basin; Amboy Township is a 290-acre productive, nutrient-rich eutrophic lake in Hillsdale County, MI. Water quality is graded D based on 2 sampling years through 2021. Compared to the 6 other monitored lakes in Hillsdale County, Lake Diane South Basin; Amboy Township ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2021-09-26. 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 2.5 ft of visibility. Chlorophyll-a: 29 µg/L. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.5 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 29 µg/L | D |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 290 acres |
Location
County Ranking
Ranked #5 of 7 lakes in Hillsdale County
Nearby Lakes in Hillsdale County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Lake Diane South Basin; Amboy Township is a man-made reservoir impounded by the Lake Diane Dam (completed 1966), built primarily for recreation on the Tributary to Clark Fork Creek; earth-type dam, 19 ft tall and 190 ft long.
- Surface area
- 290 ac
- Normal storage
- 1,700 ac-ft
- Max storage
- 3,200 ac-ft
- Drainage area
- 4.3 sq mi
- Hazard class
- Significant
- Owner
- Hillsdale County Drain Commissioner
Source: USACE National Inventory of Dams, NID ID MI00416 · Operator website · Matched by proximity (0.71 km)
EPA Impairment Status
Lake Diane South Basin; Amboy Township 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 MI041000030106-01 · Official waterbody report · Matched by proximity (0.92 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: 2021-09-26
Monitoring stations: 1