Briggs Woods Lake
Hamilton County, WisconsinHypereutrophic
Briggs Woods Lake is a 70-acre highly nutrient-loaded hypereutrophic lake in Hamilton County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Hamilton County, Briggs Woods Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-10-30. 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 1.5 ft of visibility. Chlorophyll-a: 59.1 µg/L. Trophic State Index: 71.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 59.1 µg/L | F |
| Trophic State Index (TSI) | 71 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 70 acres |
Location
County Ranking
Ranked #1 of 2 lakes in Hamilton County
Cleaner Lakes Within 30 Miles
Briggs Woods Lake holds Grade F. 2 nearby lakes hold higher grades.
- BAda Hayden Heritage Park LakeStory County · 26.8 mi · Two grade letters higher (F → B)
- DLake CorneliaWright County · 25.4 mi · Higher grade (F → D)
Nearby Lakes in Hamilton County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Hypereutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Briggs Woods Lake is a man-made reservoir impounded by the Briggs Woods Lake Dam (completed 1968), built primarily for recreation on the TR-BOONE RIVER; earth-type dam, 44 ft tall and 3,100 ft long.
- Surface area
- 70 ac
- Normal storage
- 1,310 ac-ft
- Max storage
- 2,100 ac-ft
- Drainage area
- 10.62 sq mi
- Hazard class
- Significant
- Owner
- Hamilton County Conservation Board
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID IA00437 · Operator website
EPA Impairment Status
Briggs Woods 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-UDM-1255 · 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: 2024-10-30
Monitoring stations: 1