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B

Dam Lake

Aitkin County, MinnesotaLimited DataMesotrophic

Dam Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season.

Mesotrophic conditions dominate at Dam Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 48 ft puts Dam Lake in the middle of Minnesota's depth distribution. At 598 acres, Dam Lake fits the Minnesota median for monitored lakes, with 4.1 miles of shoreline. Among the 53 graded lakes in Aitkin County, Dam Lake sits at rank 18, above the county median.

Dam Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Dam Lake, one of 17 fish species on record for the lake. A documented public access point at Dam Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been recorded 9 times at Dam Lake, with a median around Apr 16. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-13. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Good clarity, visible to about 12 ft. Trophic State Index: 41.

MetricValueGrade
Water Clarity (Secchi Depth)12 ftB
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)41Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth48 ft
Average Depth19 ft
Surface Area597.66 acres
Shoreline Length4.1 mi
Littoral Zone43%
Public AccessYes

Fish Species

bigmouth buffalo,black bullhead,black crappie,bluegill,bowfin (dogfish),brown bullhead,burbot,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,rock bass,tullibee (cisco),walleye,white sucker,yellow bullhead,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Dam Lake (14-day solunar calendar)

→ Is it safe to eat fish from Dam Lake? (mercury & PFAS guide)

Dam Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.091 m/yr5
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (15 observations).

Typical Ice-Out
Apr 16
Typical Ice-In
Nov 28

Estimated open water season: 226 days

EarliestLatest
Ice-Out2016-04-01 (2016)2008-04-26 (2008)
Ice-In2014-11-16 (2014)2015-12-23 (2015)

Most recent ice-out: 2022-04-16

Location

Loading map…

County Ranking

Ranked #18 of 53 lakes in Aitkin County

Cleaner Lakes Within 30 Miles

Dam Lake holds Grade B. One nearby lake has a higher grade.

Nearby Lakes in Aitkin County

DNR Fisheries Survey Summary

20 surveys on file from MN DNR Fisheries. Most recent: 2025-07-23 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluntnose Minnow31.50
Bluegill27.890.17 lb
Largemouth Bass11.291.01 lb
Yellow Perch5.180.13 lb
Yellow Bass2.930.85 lb
Northern Pike2.932.21 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.

Bluegill

95 fish · 38 in · 2022-07-25
26130345678

Largemouth Bass

176 fish · 619 in · 2022-07-25
34170trophy 20678910111213141516171819

Yellow Perch

8 fish · 56 in · 2022-07-25
63056

Yellow Bass

52 fish · 713 in · 2022-07-25
2010078910111213

From the 2025-07-23 survey

This report includes results from multiple targeted surveys (TS) conducted throughout Aitkin County in 2025. Bigmouth Buffalo are present throughout Aitkin County. They are most abundant in the Mississippi River but are also common in lakes that have direct or distant connections to the Mississippi River via…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Dam Lake. 4 reports on file.

EPA Impairment Status

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

Causes of impairment

Mercury

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

Source: EPA ATTAINS assessment unit MN01-0096-00 · Official waterbody report

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Lake details from Minnesota DNR LakeFinder

Ice data from Minnesota DNR Climate

Most recent sample: 2024-10-13

Monitoring stations: 1