Skip to main content
LakeQuality
F

Sylvan Lake

Hennepin County, MinnesotaHypereutrophic

Sylvan Lake earns an F: 301 µg/L of phosphorus and clarity at 1.1 ft signal heavy nutrient loading from the surrounding watershed. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. 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. Sylvan Lake ranks 79 of 95 in Hennepin County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Sylvan Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Sylvan Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Sylvan Lake — most use is by shoreline residents and their guests. 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 2023-10-03. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

Track Sylvan Lake

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

Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 1.1 ft of visibility. Phosphorus level: 301.1 µg/L. Trophic State Index: 81.

MetricValueGrade
Water Clarity (Secchi Depth)1.1 ftF
Phosphorus301.1 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)81Hypereutrophic

Very high nutrients, dense algae, poor clarity

Location

Loading map…

County Ranking

Ranked #79 of 95 lakes in Hennepin County

Cleaner Lakes Within 30 Miles

Sylvan Lake holds Grade F. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Hennepin County

State Parks Near Sylvan Lake

Hypereutrophic Lakes in Minnesota

EPA Impairment Status

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

Causes of impairment

Nutrients (phosphorus, nitrogen)

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

Source: EPA ATTAINS assessment unit MN27-0171-00 · 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

Most recent sample: 2023-10-03

Monitoring stations: 1