Corydon Reservoir
Wayne County, WisconsinEutrophic
Corydon Reservoir is a 67-acre productive, nutrient-rich eutrophic lake in Wayne County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 2 other monitored lakes in Wayne County, Corydon Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-09. 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 1.9 ft of visibility. Chlorophyll-a: 44 µg/L. Trophic State Index: 68.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.9 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 44 µg/L | F |
| Trophic State Index (TSI) | 68 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 66.9 acres |
Location
County Ranking
Ranked #2 of 3 lakes in Wayne County
Cleaner Lakes Within 30 Miles
Corydon Reservoir holds Grade F. 2 nearby lakes hold higher grades.
- DBob White LakeWayne County · 4.2 mi · Higher grade (F → D)
- DRathbun LakeAppanoose County · 23.5 mi · Higher grade (F → D)
Nearby Lakes in Wayne County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Reservoir Info (USACE NID)
Corydon Reservoir is a man-made reservoir impounded by the Corydon Reservoir Dam (completed 1974), built primarily for recreation on the TR-WEST JACKSON CREEK; earth-type dam, 26 ft tall and 750 ft long.
- Surface area
- 66.9 ac
- Normal storage
- 420 ac-ft
- Max storage
- 870 ac-ft
- Drainage area
- 2.7 sq mi
- Hazard class
- Significant
- Owner
- City of Corydon
Source: USACE National Inventory of Dams, NID ID IA01641 · Operator website
EPA Impairment Status
Corydon Reservoir 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 05-CHA-1331 · 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: 2024-09-09
Monitoring stations: 1