Nelson Lake
Nelson Lake in Pope County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 8 µg/L.
- Clarity
- 6.5 ft
- Typical in August
- 77°F
- Mean depth
- ~13 ft est.
- Public access
- Yes
Next lake in Pope County
Why Nelson Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Nelson Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Nelson Lake is a lake in Pope County, Minnesota with an estimated average depth of about 13 feet. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-07-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Nelson Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 6.5 ft. Phosphorus level: 23 µg/L. Chlorophyll-a: 8 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.5 ft | Not graded |
| Phosphorus | 23 µg/L | Not graded |
| Chlorophyll-a (Algae) | 8 µg/L | Not graded |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Nelson Lake
Compare lakeside cabins, hotels, and vacation rentals near Nelson 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.
Top-rated places to stay near Nelson Lake
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Water Temperature
Nelson Lake typically sits around 77°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 26 field readings (2019–2019) via the EPA Water Quality Portal. See the full Nelson Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~13 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Nelson Lake.
Lake Size & Watershed
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.
Recreation & Access
- Nelson LakePublic
Fishing Nelson Lake
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Nelson Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — Nelson (Main Lake)Public Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Nelson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN61-0099-00 · Official waterbody report · Matched by proximity (1.57 km)
Graded lakes near Nelson Lake
Nelson Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Pope County
Frequently asked questions about Nelson Lake
What is the water quality grade for Nelson Lake?
- Nelson Lake in Pope County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.5 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 8 µg/L.
Is Nelson Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Nelson Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Nelson Lake?
- Nelson Lake typically sits around 77°F at the surface in August, from 26 EPA Water Quality Portal field readings (2019–2019). That is a typical value for the month, not a live reading.
How deep is Nelson Lake?
- No published bathymetric survey covers Nelson Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 13 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Nelson Lake?
- Nelson Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Nelson Lake. Public access is listed as yes.
Explore Nelson Lake across LakeGrade
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Where this data comes from
3 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA3 samples · 2020
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
Named boat-access points from the USGS National Boat Ramps inventory