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LakeQuality

Hunnewell Lake

Shelby County, Missouri228 acresView mapDirections

C
Fair

Nutrients and algae sit mid-range for this region.

↑ up from D at the last regrade

Water temp
~77°F
Typical for Sep · EPA WQP
Clarity
3.2 ft
Secchi · sampled 2024
Max depth
~35 ft est.
GLOBathy model
Level
No reading
No gauge
Trend
Improving
5 years of samples
  • Eutrophic
  • Impaired · Mercury
  • #1 of 2 in the county
  • 35 ft max depth

Hunnewell Lake in Shelby County, Missouri has a water quality grade of C (Fair). Water clarity: 3.2 ft visibility. Phosphorus: 36 µg/L. Chlorophyll-a (algae): 15.4 µg/L. Surface area: 228 acres.

Clarity
3.2 ft
Typical in September
77°F
Max depth
~35 ft est.
Area
228 acres
Type
Eutrophic
Phosphorus
36 µg/L
Chlorophyll-a
15.4 µg/L
Trend
Improving
Loading map…

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Watch Hunnewell Lake’s letter

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Hunnewell Lake is a 228-acre productive, nutrient-rich eutrophic lake in Shelby County, Missouri with an estimated average depth of about 35 feet. Water quality is graded C based on 2 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 1 other monitored lakes in Shelby County, Hunnewell Lake ranks #1 for water quality.

Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2024-09-20. Grade methodology: LakeQuality methodology.

Swimming Safety

Grade only

Algae risk

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

The C is nutrients and algae, not a swimming clearance. Hunnewell Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

Compare the safest swimming lakes near St. Louis

Get alerts for Hunnewell Lake

Water Quality Grade: C (Fair)

Very murky, less than 3.2 ft of visibility. Phosphorus 36 µg/L. Chlorophyll-a 15.4 µg/L. TSI 58. The letter is not a swimming clearance.

MetricValueGrade
Water Clarity (Secchi Depth)3.2 ftNot graded
Phosphorus36 µg/LGood
Chlorophyll-a (Algae)15.4 µg/LFair
Trophic State Index (TSI)58Eutrophic

High nutrients, frequent algae, reduced clarity

Water Temperature

Hunnewell Lake typically sits around 77°F at the surface in September. Summer average is about 82°F. Usually warmest in Jul (about 85°F) and coldest in Apr (about 62°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
62°
May
72°
Jun
79°
Jul
85°
Aug
83°
Sep
77°
Oct
Nov
Dec

Typical surface water temperature by month, from 141 field readings (20102024) via the EPA Water Quality Portal. See the full Hunnewell Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth~35 ft est.
Average Depth~12 ft est.
Surface Area228 acres

Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Missouri has not published bathymetry for Hunnewell Lake.

Lake Size & Watershed

Watershed (drainage) area
4 sq mi
Shoreline
5.4 mi
Elevation
699 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.

Fishing Hunnewell Lake

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.138 m/yr5
Phosphorus Improving-3.04 µg/L/yr5
Chlorophyll-a Improving-4.22 µg/L/yr5
See year-by-year chart →

Reservoir Info (USACE NID)

Hunnewell Lake is a man-made reservoir impounded by the Hunnewell Lake Dam (completed 1953), built primarily for recreation on the TR TO BROWNE BRANCH; earth-type dam, 45 ft tall and 1,200 ft long.

Surface area
228 ac
Normal storage
2,204 ac-ft
Max storage
2,736 ac-ft
Drainage area
3.98 sq mi
Hazard class
Significant
Owner
MO DEPT OF CONSERVATION

Source: USACE National Inventory of Dams, NID ID MO10106 · Operator website

EPA Impairment Status

Hunnewell Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Source: EPA ATTAINS assessment unit MO_7029.00 · Official waterbody report

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Hunnewell Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.

  • Hunnewell Wwtf
    Hunnewell · 2.6 mi away · NPDES MO0084972
    Recent 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.

County Ranking

Ranked #1 of 2 lakes in Shelby County

Nearby Lakes in Shelby County

Frequently asked questions about Hunnewell Lake

Where is Hunnewell Lake?

Hunnewell Lake is a lake in Shelby County, Missouri. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Hunnewell Lake?

Hunnewell Lake in Shelby County, Missouri has a water quality grade of C (Fair). Water clarity: 3.2 ft visibility. Phosphorus: 36 µg/L. Chlorophyll-a (algae): 15.4 µg/L. Surface area: 228 acres.

Is Hunnewell Lake safe to swim in?

The C is nutrients and algae, not a swimming clearance. Hunnewell Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

What is the water temperature of Hunnewell Lake?

Hunnewell Lake typically sits around 77°F at the surface in September, from 141 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.

How deep is Hunnewell Lake?

No published bathymetric survey covers Hunnewell Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 35 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 228 acres.

Where this data comes from

176 measurements from 2 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Univ. of Missouri, ColumbiaUMC173 samples · 2020–2024
  • Missouri Dept. of Natural ResourcesMDNR3 samples · 2020

Analytical methods

  • Depth, Secchi disk in meters
  • 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
  • 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
  • Nitrogen and Phosphorus, Total, Whole-water, Alkaline Persulfate Digest
Monitoring station identifiers (2)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database

Regulated discharger data from EPA ECHO (ICIS-NPDES)

Lake size & watershed from HydroLAKES (HydroSHEDS)