Birch Lake
Oneida County, WisconsinLimited DataMesotrophic
The LakeGrade rubric puts Birch Lake at a C: clarity at 7.8 ft, phosphorus readings still being added, and a TSI of 48 signal an intermediate trophic state. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.
Mesotrophic conditions dominate at Birch Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 27 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Birch Lake covers 198 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Birch Lake sits at rank 73 of 134 in Oneida County, in the lower half of the local distribution.
An invasive species record — Chinese Mystery Snail — has been logged at Birch Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Birch Lake, one of 5 fish species on record for the 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 2025-10-16. Grade methodology: LakeGrade methodology.
Watch Birch Lake water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 7.8 ft. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.8 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 27 ft |
| Surface Area | 198 acres |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Birch Lake (14-day solunar calendar)
→ Is it safe to eat fish from Birch Lake? (mercury & PFAS guide)
→ Birch Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.067 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.78 µg/L/yr | 6 |
Location
County Ranking
Ranked #73 of 134 lakes in Oneida County
Cleaner Lakes Within 30 Miles
Birch Lake holds Grade C. 2 nearby lakes hold higher grades.
Nearby Lakes in Oneida County
More Wisconsin Lake Rankings
Other Grade C 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 2025).
Fish Species (DNR-rated)
EPA Impairment Status
Birch 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 WI10007217 · Official waterbody report · Matched by proximity (2.03 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
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2025-10-16
Monitoring stations: 1
Where to stay near Birch Lake
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