Spruce Lake
Oneida County, WisconsinLimited DataEutrophic
On the LakeGrade rubric Spruce Lake fails the cutoffs — a TSI of 64 and persistent algal pressure put it in the bottom tier. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. The lake bottoms out at 15 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 10 acres, Spruce Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within the 134 graded lakes of Oneida County, Spruce Lake sits at rank 134, near the bottom of the county list.
No invasive species are currently listed at Spruce Lake — the lake remains off the Wisconsin infested-waters roster. The fishery is bass-led, with 2 documented species across the lake's records. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2025-07-02. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 2.5 ft of visibility. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.5 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 15 ft |
| Surface Area | 10 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Spruce Lake (14-day solunar calendar)
→ Is it safe to eat fish from Spruce Lake? (mercury & PFAS guide)
→ Spruce Lake fishing regulations (limits, seasons, special rules)
Recreation & Access
Location
County Ranking
Ranked #134 of 134 lakes in Oneida County
Cleaner Lakes Within 30 Miles
Spruce Lake holds Grade F. One nearby lake has a higher grade.
Nearby Lakes in Oneida County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Eutrophic 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)
Reservoir Info (USACE NID)
Spruce Lake is a man-made reservoir impounded by the Spruce Lake (completed 1967), built primarily for other; earth-type dam, 11 ft tall and 300 ft long.
- Surface area
- 30 ac
- Normal storage
- 50 ac-ft
- Max storage
- 110 ac-ft
- Drainage area
- 2 sq mi
- Hazard class
- Low
- Owner
- Oneida County
All listed purposes: Other;Fish and Wildlife Pond.
Source: USACE National Inventory of Dams, NID ID WI01050 · Operator website
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2025-07-02
Monitoring stations: 1
Where to stay near Spruce Lake
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