Walsh Lake
Forest County, WisconsinLimited DataMesotrophic
Walsh Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth.
A TSI near 44 places Walsh Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. A maximum depth of 15 ft puts Walsh Lake in the middle of Wisconsin's depth distribution. Walsh Lake is small — 45 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Walsh Lake ranks 17 of 34 in Forest County — solidly in the upper half of the local distribution.
No invasive species are currently listed at Walsh Lake — the lake remains off the Wisconsin infested-waters roster. The lake's fish records list 1 species — a varied community without one dominant gamefish. 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 2021-08-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 10 ft. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | B |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 15 ft |
| Surface Area | 45 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Walsh Lake (14-day solunar calendar)
→ Is it safe to eat fish from Walsh Lake? (mercury & PFAS guide)
→ Walsh Lake fishing regulations (limits, seasons, special rules)
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.465 m/yr | 6 |
| Phosphorus | ↓ Declining | +1.8 µg/L/yr | 3 |
Location
County Ranking
Ranked #17 of 34 lakes in Forest County
Cleaner Lakes Within 30 Miles
Walsh Lake holds Grade B. 3 nearby lakes hold higher grades.
Nearby Lakes in Forest County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2021).
Fish Species (DNR-rated)
EPA Impairment Status
Walsh Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10000612 · Official waterbody report · Matched by proximity (2.73 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: 2021-08-22
Monitoring stations: 1