Casey Lake is a 39-acre highly nutrient-loaded hypereutrophic lake in Tama County, Iowa. Water quality is graded F based on 2 sampling years through 2023. Overall water quality is improving over recent sampling years. Compared to the 2 other monitored lakes in Tama County, Casey Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2023-09-25. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 1.2 ft of visibility. Chlorophyll-a: 95.5 µg/L. Trophic State Index: 75.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.2 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 95.5 µg/L | F |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 39 acres |
Where to stay near Casey Lake
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Fishing Casey Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.006 m/yr | 4 |
| Chlorophyll-a | ↑ Improving | -18.05 µg/L/yr | 4 |
Water Temperature
Casey Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 81°F) and coldest in May (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 34 field readings (2010–2023) via the EPA Water Quality Portal. See the full Casey Lake water temperature breakdown →
Location
County Ranking
Ranked #3 of 3 lakes in Tama County
Cleaner Lakes Within 30 Miles
Casey Lake holds Grade F. 3 nearby lakes hold higher grades.
- DMitchell LakeBlack Hawk County · 14.7 mi · Higher grade (F → D)
- DGreen Belt LakeBlack Hawk County · 15.3 mi · Higher grade (F → D)
- DOtter Creek LakeTama County · 18.7 mi · Higher grade (F → D)
Nearby Lakes in Tama County
Explore Casey Lake across LakeGrade
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
More records, surveys & data sources
Reservoir Info (USACE NID)
Casey Lake is a man-made reservoir impounded by the Hickory Hills Recreation Dam (completed 1970), built primarily for recreation on the TR-WOLF CREEK; earth-type dam, 29 ft tall and 1,030 ft long.
- Surface area
- 39.2 ac
- Normal storage
- 363 ac-ft
- Max storage
- 760 ac-ft
- Drainage area
- 1.27 sq mi
- Hazard class
- Low
- Owner
- Black Hawk County Conservation Board
Source: USACE National Inventory of Dams, NID ID IA01030 · Operator website · Matched by proximity (0.07 km)
EPA Impairment Status
Casey 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 02-CED-531 · Official waterbody report · Matched by proximity (0.37 km)
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Casey Lake under Clean Water Act (NPDES) discharge permits.
- Hickory Hills ParkLa Porte City · 0.2 mi away · NPDES IA0066940
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-09-25
Monitoring stations: 1