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LakeQuality

Simon Lake

F
Grade F — Algae-prone
Algae-prone · #20 of 20 lakes in the county · 1.3 ft clear · Hypereutrophic
Hypereutrophic

Simon Lake in Pope County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 109.5 µg/L. Chlorophyll-a (algae): 53.4 µg/L.

Clarity
1.3 ft
Mean depth
~12 ft est.
Type
Hypereutrophic
Trend
Declining
Public access
No

Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Simon Lake

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DGoose Lake6.1 ft clear · Pope CountyView →
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Simon Lake is a highly nutrient-loaded hypereutrophic lake in Pope County, Minnesota with an estimated average depth of about 12 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 19 other monitored lakes in Pope County, Simon Lake ranks #20 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.

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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.

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom

Compare the safest swimming lakes near Willmar

Get alerts for Simon Lake

Water Quality Grade: F (Algae-prone)

Very murky, less than 1.3 ft of visibility. Phosphorus level: 109.5 µg/L. Chlorophyll-a: 53.4 µg/L. Trophic State Index: 72.

MetricValueGrade
Water Clarity (Secchi Depth)1.3 ftNot graded
Phosphorus109.5 µg/LPoor
Chlorophyll-a (Algae)53.4 µg/LPoor
Trophic State Index (TSI)72Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Simon Lake

Compare lakeside cabins, hotels, and vacation rentals near Simon Lake in Pope County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Simon Lake are listed below.

Top-rated places to stay near Simon Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Lake Details

CharacteristicValue
Average Depth~12 ft est.
Public AccessNo

Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Simon Lake.

Lake Size & Watershed

Watershed (drainage) area
6 sq mi
Surface area
497 acres
Mean depth (modeled estimate)
~12 ft est.
Shoreline
4 mi
Elevation
1,073 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 Simon Lake

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Simon Lake. 2 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.037 m/yr6
Phosphorus Improving-4.37 µg/L/yr6
Chlorophyll-a Declining+5.46 µg/L/yr6
See year-by-year chart →

EPA Impairment Status

Simon Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Nutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN61-0034-00 · Official waterbody report

County Ranking

Ranked #20 of 20 lakes in Pope County

Nearby Lakes With Higher Grades

Simon Lake holds Grade F. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.

See full comparison →

Nearby Lakes in Pope County

Frequently asked questions about Simon Lake

What is the water quality grade for Simon Lake?

Simon Lake in Pope County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 109.5 µg/L. Chlorophyll-a (algae): 53.4 µg/L.

Is Simon Lake safe to swim in?

Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Simon Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 53.4 µg/L. Always check local health department advisories before swimming.

How deep is Simon Lake?

No published bathymetric survey covers Simon Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 12 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.

Where this data comes from

90 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA90 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Two Reagent Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)

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

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder