Hardwood Lake
Carlton County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Hardwood Lake. Here is what has been measured.
- Eutrophic
- 45 ft max depth
- Limited data
Hardwood Lake in Carlton County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility. Phosphorus: 200 µg/L. Chlorophyll-a (algae): 5.1 µg/L.
Hardwood Lake is a productive, nutrient-rich eutrophic lake in Carlton County, Minnesota with an estimated average depth of about 45 feet. Overall water quality is declining over recent sampling years. Compared to the 21 other monitored lakes in Carlton County, Hardwood Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-07-15. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Hardwood Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Hardwood Lake
These are the measurements Minnesota PCA publishes for Hardwood Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.1 ft. Phosphorus 200 µg/L. Chlorophyll-a 5.1 µg/L. TSI 60.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 200µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 5.1µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Lake Details
Max depth
~45 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Hardwood Lake.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Surface area
59 acres
HydroLAKES / HydroSHEDS
Shoreline
1.1 mi
HydroLAKES / HydroSHEDS
Elevation
1,280 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.
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Fishing Hardwood Lake
Water quality readings over time
3 seasons of samples on record (2020–2024). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Worsening+64.29 µg/L/yr3 years
Chlorophyll-a
Worsening+0.66 µg/L/yr3 years
Nearby Lakes in Carlton County
Frequently asked questions about Hardwood Lake
Where is Hardwood Lake?
- Hardwood Lake is a lake in Carlton County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Hardwood Lake?
- Hardwood Lake in Carlton County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 5.1 ft visibility. Phosphorus: 200 µg/L. Chlorophyll-a (algae): 5.1 µg/L.
Is Hardwood Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Hardwood Lake?
- No published bathymetric survey covers Hardwood Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 45 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
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Where this data comes from
38 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Fond du Lac Band of Chippewa (MN)
FONDULAC_WQX38 samples · 2020–2024
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
- 10200 H ~ Chlorophyll a-b-c Determination
- Color, APHA Platinum-Cobalt
- For determination of Copper by the Bicinchoninate method.
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder