Arrowhead Lake
Sac County, WisconsinEutrophic
Arrowhead Lake is a 110-acre productive, nutrient-rich eutrophic lake in Sac County, IA. Water quality is graded C based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Sac County, Arrowhead Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-04. Grade methodology: LakeGrade methodology.
Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.6 ft. Chlorophyll-a: 7.1 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.6 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 7.1 µg/L | B |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 110 acres |
Location
County Ranking
Ranked #1 of 2 lakes in Sac County
Nearby Lakes in Sac County
More Wisconsin Lake Rankings
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Arrowhead Lake is a man-made reservoir impounded by the Provost Bay Dam, built primarily for other on the unnamed tributary; earth-type dam, 10 ft tall and 650 ft long.
- Surface area
- 110 ac
- Max storage
- 257 ac-ft
- Drainage area
- 0.54 sq mi
- Hazard class
- Low
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA04396 · Operator website · Matched by proximity (0.67 km)
EPA Impairment Status
Arrowhead Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 04-RAC-1134 · Official waterbody report · Matched by proximity (2.12 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: 2024-09-04
Monitoring stations: 1