Mariposa Lake
Jasper County, WisconsinEutrophic
Mariposa Lake is a 19-acre productive, nutrient-rich eutrophic lake in Jasper County, IA. Water quality is graded C based on 2 sampling years through 2024. Compared to the 7 other monitored lakes in Jasper County, Mariposa Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-08-25. Grade methodology: LakeGrade methodology.
Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5.1 ft. Chlorophyll-a: 8.9 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.1 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 8.9 µg/L | B |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 18.7 acres |
Location
County Ranking
Ranked #1 of 8 lakes in Jasper County
Nearby Lakes in Jasper County
More Wisconsin Lake Rankings
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Mariposa Lake is a man-made reservoir impounded by the Mariposa Lake Dam (completed 1952), built primarily for recreation on the TR-ALLOWAY CREEK; earth-type dam, 25 ft tall and 525 ft long.
- Surface area
- 18.7 ac
- Normal storage
- 112 ac-ft
- Max storage
- 188 ac-ft
- Drainage area
- 0.92 sq mi
- Hazard class
- Low
- Owner
- Jasper County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA01348 · Operator website
EPA Impairment Status
Mariposa 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-867 · 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: 2024-08-25
Monitoring stations: 1