Nelson Lake
Nelson Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11 ft visibility. Maximum depth: 52 ft. Surface area: 85.96 acres.
- Clarity
- 11 ft
- Typical in August
- 76°F
- Max depth
- 52 ft
- Area
- 86 acres
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Douglas 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, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not 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 86-acre lake in Douglas County, Minnesota with a maximum depth of 52 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-30. 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.
Good clarity, visible to about 11 ft. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Nelson Lake
Compare lakeside cabins, hotels, and vacation rentals near Nelson Lake in Douglas 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 76°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 81°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 18 field readings (2024–2025) via the EPA Water Quality Portal. See the full Nelson Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 52 ft |
| Surface Area | 86 acres |
| Shoreline Length | 1.6 mi |
| Littoral Zone | 66% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake Mary (North)Public
- Lakota Lake (South)Public
Fishing Nelson Lake
DNR Fisheries Survey Summary
1 survey on file from MN DNR Fisheries. Most recent: 1990-07-23 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Bass | 22.88 | 0.47 lb |
| Bluegill | 17.06 | 0.18 lb |
| Northern Pike | 8.19 | 1.23 lb |
| Common Carp | 5.50 | 1.39 lb |
| Pumpkinseed | 3.94 | 0.18 lb |
| Hybrid Sunfish | 3.12 | 0.2 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 1990-07-23 survey
The 31 year gap in population assessments make analyzing gradual trends impossible. However some very noticeable changes in the fish populations have occurred. The Yellow Perch index was 103.5 fish/gillnet in 1959. No Yellow Perch were sampled in the 1990 assessment. No Bluegill were observed in trapnets in 1959. In…
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).
- —Fisheries Lake Survey — NelsonFisheries Lake Survey · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.117 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.31 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.08 µg/L/yr | 6 |
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 MN21-0106-02 · Official waterbody report · Matched by proximity (1.19 km)
Graded lakes near Nelson Lake
Nelson Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Douglas County
Frequently asked questions about Nelson Lake
What is the water quality grade for Nelson Lake?
- Nelson Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 11 ft visibility. Maximum depth: 52 ft. Surface area: 85.96 acres.
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. Always check local health department advisories before swimming.
What is the water temperature of Nelson Lake?
- Nelson Lake typically sits around 76°F at the surface in August, from 18 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Nelson Lake?
- Nelson Lake has a maximum depth of 52 feet. The lake covers 85.96 acres.
Are there boat ramps on Nelson Lake?
- Nelson Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Mary (North), Lakota Lake (South). Public access is listed as yes.
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Where this data comes from
18 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA18 samples · 2024–2025
Analytical methods
- Field measurement/observation, generic method
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