Sweeney Lake
Hennepin County, MinnesotaMesotrophic
On the LakeGrade scale Sweeney Lake grades a B, with clarity at 6.9 ft and 23 µg/L of phosphorus placing it above the Minnesota median. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.
A TSI near 49 places Sweeney Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Sweeney Lake reaches 28 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 68 acres, Sweeney Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Among the 95 graded lakes in Hennepin County, Sweeney Lake ranks 9 — in the top quartile locally.
No invasive species are currently listed at Sweeney Lake — the lake remains off the Minnesota infested-waters roster. Bass fishing is part of the appeal: the species list runs to 12, anchored by largemouth and/or smallmouth bass. 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 2023-09-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 6.9 ft. Phosphorus level: 23 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.9 ft | C |
| Phosphorus | 23 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 28 ft |
| Surface Area | 67.64 acres |
| Shoreline Length | 2.1 mi |
| Littoral Zone | 50% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Sweeney Lake (14-day solunar calendar)
→ Is it safe to eat fish from Sweeney Lake? (mercury & PFAS guide)
→ Sweeney 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 | +0.356 m/yr | 5 |
| Phosphorus | ↑ Improving | -4.3 µg/L/yr | 4 |
Location
County Ranking
Ranked #9 of 95 lakes in Hennepin County
Nearby Lakes in Hennepin County
More Minnesota Lake Rankings
State Parks Near Sweeney Lake
Other Grade B Lakes in Minnesota
Mesotrophic Lakes in Minnesota
DNR Fisheries Survey Summary
2 surveys on file from MN DNR Fisheries. Most recent: 1991-07-01 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 60.35 | 0.11 lb |
| Black Crappie | 10.71 | 0.2 lb |
| Black Bullhead | 8.71 | 0.33 lb |
| GIS | 4.00 | 0.34 lb |
| Northern Pike | 3.28 | 3.17 lb |
| Common Carp | 2.48 | 5.07 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
From the 1991-07-01 survey
THE PRESENT FISH POPULATION IS DOMINATED BY BLHS, SMALL CEN, CATOSTOMIDS AND CYPRINIDS. BLGS AND BLBS WERE SAMPLED WELL ABOVE MEDIAN LEVELS; BLG AVERAGED 12.06 FISH PER POUND AND HAVE A PSD=10.1. BLBS AVERAGED 8.5-8.9 INCHES TOTAL LENGTH AND 2.88 FISH PER POUND. CARP WERE SAMPLED SLIGHTLY ABOVE MEDIAN LEVELS FOR…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Sweeney Lake. 1 report on file.
- —Fisheries Lake Survey — SweeneyFisheries Lake Survey · MN DNR LakeFinder
EPA Impairment Status
Sweeney 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 MN27-0035-01 · 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: 2023-09-06
Monitoring stations: 1