Harrison County Lake is a 292-acre highly nutrient-loaded hypereutrophic lake in Harrison County, Missouri. Water quality is graded F based on 3 sampling years through 2021. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Harrison County, Harrison County Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2021-09-01. Grade methodology: LakeGrade methodology.
Watch Harrison County 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 1.5 ft of visibility. Phosphorus level: 70 µg/L. Chlorophyll-a: 134.4 µg/L. Trophic State Index: 72.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | F |
| Phosphorus | 70 µg/L | D |
| Chlorophyll-a (Algae) | 134.4 µg/L | F |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 292 acres |
| Public Access | Yes |
Where to stay near Harrison County Lake
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Fishing Harrison County Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | 0 m/yr | 4 |
| Phosphorus | ↓ Declining | +7.77 µg/L/yr | 5 |
| Chlorophyll-a | → Stable | +0.35 µg/L/yr | 5 |
Recreation & Access
Location
County Ranking
Ranked #3 of 3 lakes in Harrison County
Cleaner Lakes Within 30 Miles
Harrison County Lake holds Grade F. 4 nearby lakes hold higher grades.
- BNorth Bethany City ReservoirHarrison County · 6.5 mi · Two grade letters higher (F → B)
- BLake MarieMercer County · 28.6 mi · Two grade letters higher (F → B)
- DHarrison County Lake IntakeHarrison County · 0.1 mi · Higher grade (F → D)
- DLake PahoMercer County · 22.8 mi · Higher grade (F → D)
Nearby Lakes in Harrison County
Explore Harrison County Lake across LakeGrade
Species activity outlook by water temperature and season
Where to stay at Missouri's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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More records, surveys & data sources
Reservoir Info (USACE NID)
Harrison County Lake is a man-made reservoir impounded by the West Fork of Big Creek C-1 Dam (completed 1992), built primarily for flood risk reduction on the LITTLE CREEK; earth-type dam, 49 ft tall and 1,500 ft long.
- Surface area
- 292 ac
- Normal storage
- 2,842 ac-ft
- Max storage
- 9,994 ac-ft
- Drainage area
- 17.2 sq mi
- Hazard class
- High
Source: USACE National Inventory of Dams, NID ID MO12370 · Operator website · Matched by proximity (0.24 km)
EPA Impairment Status
Harrison County Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MO_7386.00 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
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: 2021-09-01
Monitoring stations: 1