Crystal Lake Max Depth
Hancock County, WisconsinEutrophic
Crystal Lake Max Depth is a 10-acre productive, nutrient-rich eutrophic lake in Hancock County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Hancock County, Crystal Lake Max Depth ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-10-22. 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 1.6 ft of visibility. Chlorophyll-a: 50.3 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 50.3 µg/L | F |
| Trophic State Index (TSI) | 70 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 9.7 acres |
Location
County Ranking
Ranked #1 of 2 lakes in Hancock County
Cleaner Lakes Within 30 Miles
Crystal Lake Max Depth holds Grade F. 3 nearby lakes hold higher grades.
- ABlue Pit LakeCerro Gordo County · 29.5 mi · Two grade letters higher (F → A)
- DClear LakeCerro Gordo County · 20.2 mi · Higher grade (F → D)
- DBlack Pit LakeCerro Gordo County · 29.3 mi · Higher grade (F → D)
Nearby Lakes in Hancock County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Crystal Lake Max Depth is a man-made reservoir impounded by the Crystal Lake Sediment Control Dam (completed 2003) on the Tr- West Fork Iowa River; earth-type dam, 27 ft tall and 625 ft long.
- Surface area
- 9.7 ac
- Normal storage
- 89 ac-ft
- Max storage
- 148 ac-ft
- Drainage area
- 0.36 sq mi
- Hazard class
- Low
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA03525 · Operator website · Matched by proximity (0.82 km)
EPA Impairment Status
Crystal Lake Max Depth is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 02-IOW-781 · Official waterbody report · Matched by proximity (0.15 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: 2024-10-22
Monitoring stations: 1