Aaron Lake
Aaron Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7 ft visibility. Maximum depth: 16 ft. Surface area: 610.3 acres.
- Clarity
- 7 ft
- Typical in August
- 75°F
- Max depth
- 16 ft
- Area
- 610 acres
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 25
- Open water
- 211 days
Next lake in Douglas County
Why Aaron 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 Aaron 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.
Aaron Lake is a 610-acre lake in Douglas County, Minnesota with a maximum depth of 16 feet (9-foot average). Overall water quality is declining over recent sampling years. The lake supports 15 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing.
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
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Aaron Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 7 ft. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Aaron Lake
Compare lakeside cabins, hotels, and vacation rentals near Aaron 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 Aaron Lake
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Water Temperature
Aaron Lake typically sits around 75°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in May (about 60°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 14 field readings (2022–2025) via the EPA Water Quality Portal. See the full Aaron Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 16 ft |
| Average Depth | 9 ft |
| Surface Area | 610 acres |
| Shoreline Length | 4.9 mi |
| Littoral Zone | 77% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake AaronPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Aaron 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.
DNR Fisheries Survey Summary
13 surveys on file from MN DNR Fisheries. Most recent: 2024-05-14 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| GOS | 97.86 | — |
| Yellow Perch | 97.70 | 0.14 lb |
| OTM | 46.75 | — |
| IOD | 38.49 | — |
| Spottail Shiner | 35.13 | — |
| Bluegill | 34.12 | 0.16 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Yellow Perch
Bluegill
From the 2024-05-14 survey
A targeted survey was conducted May 14-15 on Aaron Lake to assess the Bluegill and Black Crappie populations. Bluegill were abundant (90.5/trap net). Lengths ranged from 3.4 to 8.9 inches, with an average of 6.8 inches. Growth is below average for the area, but Bluegill were recorded out to age 12. Black Crappie catch…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Aaron Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — AaronFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — AaronFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — AaronPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.38 m/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (11 observations).
Estimated open water season: 211 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-07 (2024) | 2008-04-30 (2008) |
| Ice-In | 2022-11-18 (2022) | 2021-12-07 (2021) |
Most recent ice-out: 2025-04-07
Reservoir Info (USACE NID)
Aaron Lake is a man-made reservoir impounded by the Lake Aaron (completed 1964), built primarily for recreation on the Chippewa River-TR; gravity-type dam, 8 ft tall and 10 ft long.
- Surface area
- 611 ac
- Normal storage
- 178,500 ac-ft
- Max storage
- 190,000 ac-ft
- Drainage area
- 6.5 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00173 · Operator website
EPA Impairment Status
Aaron Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN21-0242-00 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Aaron Lake under Clean Water Act (NPDES) discharge permits.
- Millerville WwtpMillerville · 1.8 mi away · NPDES MN0054305
- Joe Wagner FarmBrandon · 2.7 mi away · NPDES MN0070866
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near Aaron Lake
Aaron Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Douglas County
Frequently asked questions about Aaron Lake
What is the water quality grade for Aaron Lake?
- Aaron Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 7 ft visibility. Maximum depth: 16 ft. Surface area: 610.3 acres.
Is Aaron Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Aaron 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 Aaron Lake?
- Aaron Lake typically sits around 75°F at the surface in August, from 14 EPA Water Quality Portal field readings (2022–2025). That is a typical value for the month, not a live reading.
How deep is Aaron Lake?
- Aaron Lake has a maximum depth of 16 feet and an average depth of 9 feet. The lake covers 610.3 acres.
What fish are in Aaron Lake?
- Fish species found in Aaron Lake include black bullhead, black crappie, bluegill, brown bullhead, common carp, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Aaron Lake is located in Douglas County, Minnesota.
When does Aaron Lake thaw?
- Aaron Lake typically has ice-out around Apr 25. Ice typically forms around Nov 22. The open water season is approximately 211 days.
Are there boat ramps on Aaron Lake?
- Aaron Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Aaron. Public access is listed as yes.
Explore Aaron Lake across LakeGrade
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Where this data comes from
39 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 Water
MNPCA39 samples · 2020–2025
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate