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LakeQuality
B

Jones Slough Lake

Grant County, WisconsinMesotrophic

Jones Slough Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. Of the three parameters, phosphorus is the worst — at 31 µg/L of phosphorus, it keeps the lake susceptible to algal blooms in warm years.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. 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. Among the 3 graded lakes in Grant County, Jones Slough Lake sits at rank 1, above the county median.

Jones Slough Lake has no invasive species recorded in Wisconsin state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Jones Slough Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. 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, Wisconsin DNR Surface Water, last sampled 2023-10-30. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Crystal clear, you can see 16.1 ft down. Phosphorus level: 31 µg/L. Trophic State Index: 45.

MetricValueGrade
Water Clarity (Secchi Depth)16.1 ftA
Phosphorus31 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)45Mesotrophic

Moderate nutrients, good water quality

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.3 m/yr2
Phosphorus Declining+35.6 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #1 of 3 lakes in Grant County

Cleaner Lakes Within 30 Miles

Jones Slough Lake holds Grade B. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Grant County

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2023-10-30

Monitoring stations: 1