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LakeQuality
F

Gaystock Lake

Carver County, MinnesotaHypereutrophic

Gaystock Lake grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI above 70 puts Gaystock Lake in hypereutrophic territory: visible blooms are common, and clarity rarely climbs even in early summer. 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. Gaystock Lake ranks 39 of 40 in Carver County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Gaystock Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Gaystock Lake, which usually reflects a lack of formal fisheries survey work rather than an empty 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 2022-10-05. Grade methodology: LakeGrade methodology.

Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 0.7 ft of visibility. Phosphorus level: 236 µg/L. Trophic State Index: 83.

MetricValueGrade
Water Clarity (Secchi Depth)0.7 ftF
Phosphorus236 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)83Hypereutrophic

Very high nutrients, dense algae, poor clarity

Location

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County Ranking

Ranked #39 of 40 lakes in Carver County

Nearby Lakes in Carver County

Hypereutrophic Lakes in Minnesota

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2022-10-05

Monitoring stations: 1