Upper Pine Lake is a 110-acre highly nutrient-loaded hypereutrophic lake in Hardin County, Iowa. Water quality is graded F based on 2 sampling years through 2024. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 6 other monitored lakes in Hardin County, Upper Pine Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2024-10-28. Grade methodology: LakeGrade methodology.
Watch Upper Pine Lake water quality
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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 1.3 ft of visibility. Chlorophyll-a: 66.7 µg/L. Trophic State Index: 73.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.3 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 66.7 µg/L | F |
| Trophic State Index (TSI) | 73 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 110 acres |
| Public Access | Yes |
Where to stay near Upper Pine Lake
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Fishing Upper Pine Lake
Water Quality Trend: → Stable
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.034 m/yr | 5 |
| Chlorophyll-a | ↓ Declining | +11.78 µg/L/yr | 5 |
Recreation & Access
Water Temperature
Upper Pine Lake averages about 76°F at the surface in summer, usually warmest in Jul (about 80°F) and coldest in May (about 62°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 Upper Pine Lake water temperature breakdown →
Location & Depth Map
Free interactive depth-contour map of Upper Pine Lake, reaching a maximum surveyed depth of 16 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Iowa DNR.
County Ranking
Ranked #1 of 7 lakes in Hardin County
Cleaner Lakes Within 30 Miles
Upper Pine Lake holds Grade F. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Hardin County
Explore Upper Pine 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)
Upper Pine Lake is a man-made reservoir impounded by the Upper Pine Lake Dam (completed 1934), built primarily for recreation on the PINE CREEK; earth-type dam, 42 ft tall and 490 ft long.
- Surface area
- 110 ac
- Normal storage
- 890 ac-ft
- Max storage
- 2,710 ac-ft
- Drainage area
- 14 sq mi
- Hazard class
- Significant
- Owner
- Iowa Department of Natural Resources
Source: USACE National Inventory of Dams, NID ID IA00441 · Operator website
EPA Impairment Status
Upper Pine 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-IOW-760 · Official waterbody report
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 Upper Pine Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Steamboat Rock City Of StpSteamboat Rock · 2.2 mi away · NPDES IA0033324Recent violation
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2024-10-28
Monitoring stations: 1