Crystal Lake
Hennepin County, MinnesotaEutrophic
Crystal Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.
At a TSI of 61, Crystal Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Crystal Lake reaches 39 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake is compact at 79 acres, with 1.6 miles of shoreline and little volume to buffer nutrient inputs. Crystal Lake ranks 24 of 95 in Hennepin County — solidly in the upper half of the local distribution.
Crystal Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Muskie are on the species list at Crystal Lake, among the lake's 12 documented fish. Public access is available — the lake is on the Minnesota PCA public-access list. 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 2024-09-18. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 3.5 ft. Phosphorus level: 58 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 ft | D |
| Phosphorus | 58 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 39 ft |
| Average Depth | 9.8 ft |
| Surface Area | 79.12 acres |
| Shoreline Length | 1.6 mi |
| Littoral Zone | 67% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Crystal Lake (14-day solunar calendar)
→ Is it safe to eat fish from Crystal Lake? (mercury & PFAS guide)
→ Crystal Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.094 m/yr | 4 |
| Phosphorus | ↓ Declining | +2.5 µg/L/yr | 3 |
Ice Season
Historical ice data from Minnesota DNR (6 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2007-03-29 (2007) | 2022-04-10 (2022) |
| Ice-In | 2006-12-01 (2006) | 2007-12-04 (2007) |
Most recent ice-out: 2022-04-10
Location
County Ranking
Ranked #24 of 95 lakes in Hennepin County
Cleaner Lakes Within 30 Miles
Crystal Lake holds Grade C. 3 nearby lakes hold higher grades.
- BSweeney LakeHennepin County · mi · Higher grade (C → B)
- BSweeney-Twin LakeHennepin County · mi · Higher grade (C → B)
- CWirth LakeHennepin County · mi · Higher overall water quality score
Nearby Lakes in Hennepin County
More Minnesota Lake Rankings
State Parks Near Crystal Lake
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2022-08-17 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 67.88 | 0.11 lb |
| Black Crappie | 55.27 | 0.14 lb |
| GOS | 19.01 | 0.09 lb |
| Yellow Perch | 13.76 | 0.14 lb |
| Black Bullhead | 12.06 | 0.35 lb |
| Northern Pike | 3.30 | 3.79 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
Black Crappie
GOS
Yellow Perch
From the 2022-08-17 survey
Crystal Lake is a 78-acre lake located in Robbinsdale. City parks are situated to the north and south of the lake, and both provide shore fishing access. The park to the north includes a fishing pier (Installed in 2019), and the park to the south includes a boat access with trailer parking. Crystal Lake is primarily a…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Crystal Lake. 3 reports on file.
- —Fisheries Lake Survey — CrystalFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — CrystalFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — CrystalPublic Water Access Sites · MN DNR LakeFinder
EPA Impairment Status
Crystal Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN27-0034-00 · 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: 2024-09-18
Monitoring stations: 1