Marshan Lake
Anoka County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Marshan Lake. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- Eurasian watermilfoil
- 40 ft max depth
- Limited data
Marshan Lake in Anoka County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.2 ft visibility.
Marshan Lake is a lake in Anoka County, Minnesota with an estimated average depth of about 40 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-08-02. Methodology: how these readings are compared.
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Marshan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Marshan 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 Marshan Lake
These are the measurements Minnesota PCA publishes for Marshan Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.2 ft of visibility. TSI 74.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 74 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Marshan Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~40 ft est.
Public access
No
Listed by Minnesota PCA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Marshan Lake.
Lake Size & Watershed
Watershed (drainage) area
76 sq mi
HydroLAKES / HydroSHEDS
Surface area
188 acres
HydroLAKES / HydroSHEDS
Shoreline
2.3 mi
HydroLAKES / HydroSHEDS
Elevation
863 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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Stays near Marshan Lake
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Fishing Marshan Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: Improving
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Improving-26.4 µg/L/yr4 years
Chlorophyll-a
Improving-3.42 µg/L/yr4 years
EPA Impairment Status
Marshan Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN02-0007-00 · Official waterbody report
Nearby Lakes in Anoka County
Frequently asked questions about Marshan Lake
Where is Marshan Lake?
- Marshan Lake is a lake in Anoka County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Marshan Lake?
- Marshan Lake in Anoka County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 1.2 ft visibility.
Is Marshan Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Marshan Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Marshan Lake?
- No published bathymetric survey covers Marshan Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 40 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Can I fish at Marshan Lake?
- Public access to Marshan Lake is listed as no on the lake record, so confirm before you make the trip. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
4 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2023
Analytical methods
- Field measurement/observation, generic 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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder