Mckinley Lake is a 38-acre highly nutrient-loaded hypereutrophic lake in Union County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 5 other monitored lakes in Union County, Mckinley Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-07-08. 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 ft of visibility. Chlorophyll-a: 69.3 µg/L. Trophic State Index: 75.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 69.3 µg/L | F |
| Trophic State Index (TSI) | 75 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 38 acres |
Where to stay near Mckinley Lake
Compare lakeside cabins, hotels, and vacation rentals near Mckinley Lake in Union County, Iowa — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Fishing Mckinley Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.042 m/yr | 5 |
| Chlorophyll-a | ↑ Improving | -5.66 µg/L/yr | 5 |
Water Temperature
Mckinley Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 79°F) and coldest in Jun (about 76°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 11 field readings (2018–2023) via the EPA Water Quality Portal. See the full Mckinley Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Mckinley Lake, reaching a maximum surveyed depth of 4 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #6 of 6 lakes in Union County
Cleaner Lakes Within 30 Miles
Mckinley Lake holds Grade F. 2 nearby lakes hold higher grades.
- DThree Mile LakeUnion County · 9.1 mi · Higher grade (F → D)
- DThayer LakeUnion County · 16.9 mi · Higher grade (F → D)
Nearby Lakes in Union County
Explore Mckinley 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)
Mckinley Lake is a man-made reservoir impounded by the Mc Kinley Lake Dam (completed 1920), built primarily for recreation on the TR-WEST PLATTE RIVER; earth-type dam, 19 ft tall and 780 ft long.
- Surface area
- 38 ac
- Normal storage
- 200 ac-ft
- Max storage
- 290 ac-ft
- Drainage area
- 3.46 sq mi
- Hazard class
- Significant
- Owner
- City of Creston
Source: USACE National Inventory of Dams, NID ID IA01376 · Operator website
EPA Impairment Status
Mckinley Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IA 05-PLA-1470 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Mckinley Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Creston City Of StpCreston · 0.4 mi away · NPDES IA0035238MajorRecent violation
- Wdc Acquisition, Llc Dba WellmanCreston · 2.4 mi away · NPDES IA0077313
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: 2024-07-08
Monitoring stations: 1