Skip to main content
LakeQuality
C

Duck Lake

Hennepin County, MinnesotaEutrophic

The LakeGrade rubric puts Duck Lake at a C: clarity at 6.2 ft, 34 µg/L of phosphorus, and a TSI of 53 signal an intermediate trophic state. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Duck Lake ranks 29 of 95 in Hennepin County — solidly in the upper half of the local distribution.

Duck Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. The state fisheries records do not list documented species for Duck Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Duck Lake — most use is by shoreline residents and their guests. 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 2023-09-14. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

Track Duck Lake

Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.

Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Murky, only visible to about 6.2 ft. Phosphorus level: 34 µg/L. Trophic State Index: 53.

MetricValueGrade
Water Clarity (Secchi Depth)6.2 ftD
Phosphorus34 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)53Eutrophic

High nutrients, frequent algae, reduced clarity

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Eurasian watermilfoil

Water Quality Trend: Improving

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable+0.029 m/yr3
Phosphorus Improving-3.11 µg/L/yr3

Location

Loading map…

County Ranking

Ranked #29 of 95 lakes in Hennepin County

Cleaner Lakes Within 30 Miles

Duck Lake holds Grade C. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Hennepin County

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Duck Lake. 1 report on file.

EPA Impairment Status

Duck 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 MN27-0071-00 · Official waterbody report · Matched by proximity (1.16 km)

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

Most recent sample: 2023-09-14

Monitoring stations: 1