Rock Creek Max Depth Lake
Jasper County, WisconsinHypereutrophic
Rock Creek Max Depth Lake is a 640-acre highly nutrient-loaded hypereutrophic lake in Jasper County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 7 other monitored lakes in Jasper County, Rock Creek Max Depth Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-05. 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 1.1 ft of visibility. Chlorophyll-a: 107.5 µg/L. Trophic State Index: 76.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.1 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 107.5 µg/L | F |
| Trophic State Index (TSI) | 76 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 640 acres |
Location
County Ranking
Ranked #2 of 8 lakes in Jasper County
Cleaner Lakes Within 30 Miles
Rock Creek Max Depth Lake holds Grade F. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Jasper County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Hypereutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Rock Creek Max Depth Lake is a man-made reservoir impounded by the Rock Creek Dam, built primarily for recreation on the ROCK CREEK; earth-type dam, 33 ft tall and 1,500 ft long.
- Surface area
- 640 ac
- Normal storage
- 5,500 ac-ft
- Max storage
- 13,700 ac-ft
- Drainage area
- 41.4 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA00537 · Operator website · Matched by proximity (0.19 km)
EPA Impairment Status
Rock Creek Max Depth Lake 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 03-NSK-865 · Official waterbody report · Matched by proximity (1.73 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: 2024-09-05
Monitoring stations: 1