Alden Lake
St. Louis County, MinnesotaLimited DataEutrophic
On the scoring rubric Alden Lake grades a D: clarity at 4.9 ft and phosphorus readings still being added keep it in the lower bracket for St. Louis County.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Alden Lake reaches 29 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 190 acres, Alden Lake fits the Minnesota median for monitored lakes, with 4.1 miles of shoreline. Within the 187 graded lakes of St. Louis County, Alden Lake sits at rank 170, near the bottom of the county list.
No invasive species are currently listed at Alden Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Alden Lake, one of 11 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 4.9 ft. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 29 ft |
| Average Depth | 6 ft |
| Surface Area | 189.7 acres |
| Shoreline Length | 4.1 mi |
| Littoral Zone | 84% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Alden Lake (14-day solunar calendar)
→ Is it safe to eat fish from Alden Lake? (mercury & PFAS guide)
→ Alden Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.034 m/yr | 5 |
Location
County Ranking
Ranked #170 of 187 lakes in St. Louis County
Nearby Lakes in St. Louis County
More Minnesota Lake Rankings
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
3 surveys on file from MN DNR Fisheries. Most recent: 2001-07-30 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 5.18 | 0.15 lb |
| White Sucker | 4.40 | 2.48 lb |
| Smallmouth Bass | 2.31 | 1.17 lb |
| Walleye | 1.77 | 1.97 lb |
| Bluegill | 1.60 | 0.25 lb |
| Shorthead Redhorse | 1.38 | 1.92 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
White Sucker
Smallmouth Bass
Walleye
From the 2001-07-30 survey
Big Alden is a 180 acre lake with 159 (88%) acres of littoral area and a maximum depth of 29 feet . Big Alden Lake is located 14 miles northeast of Duluth off St. Louis County Highway #44. Big Alden does not have a developed public access along the shoreline but can be accessed by canoe through the Cloquet River. The…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Alden Lake. 2 reports on file.
- —Fisheries Lake Survey — AldenFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Alden (0536)Aquatic Plant Report · MN DNR LakeFinder
EPA Impairment Status
Alden 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 MN69-0131-00 · 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
Most recent sample: 2024-10-09
Monitoring stations: 1