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LakeQuality
D

Gilfillan Lake

Ramsey County, MinnesotaEutrophic

Gilfillan Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Minnesota norms.

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. Gilfillan Lake ranks 37 of 49 in Ramsey County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Gilfillan Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Gilfillan Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Gilfillan 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 2024-09-25. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Very murky, less than 3 ft of visibility. Phosphorus level: 48 µg/L. Trophic State Index: 61.

MetricValueGrade
Water Clarity (Secchi Depth)3 ftF
Phosphorus48 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)61Eutrophic

High nutrients, frequent algae, reduced clarity

Water Quality Trend: Improving

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.055 m/yr5
Phosphorus Improving-1.75 µg/L/yr5

Location

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County Ranking

Ranked #37 of 49 lakes in Ramsey County

Nearby Lakes in Ramsey County

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-09-25

Monitoring stations: 1