Alexander Lake
Lincoln County, WisconsinEutrophic
Alexander Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.
At a TSI of 58, Alexander Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. Alexander Lake reaches 36 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 618 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Alexander Lake ranks 16 of 18 in Lincoln County — at the lower end of the locally monitored distribution.
Eurasian watermilfoil has been documented at Alexander Lake, requiring shoreline management to keep dense mats from crowding native vegetation. Walleye are documented at Alexander Lake, one of 6 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-09-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 4 ft. Phosphorus level: 46.2 µg/L. Trophic State Index: 58.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | D |
| Phosphorus | 46.2 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 58 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 36 ft |
| Surface Area | 618 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Alexander Lake (14-day solunar calendar)
→ Is it safe to eat fish from Alexander Lake? (mercury & PFAS guide)
→ Alexander 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.
Location
County Ranking
Ranked #16 of 18 lakes in Lincoln County
Cleaner Lakes Within 30 Miles
Alexander Lake holds Grade C. 3 nearby lakes hold higher grades.
- ABass LakeLincoln County · mi · Two grade letters higher (C → A)
- ALong LakeLincoln County · mi · Two grade letters higher (C → A)
- BLake PesobicLincoln County · mi · Higher grade (C → B)
Nearby Lakes in Lincoln County
More Wisconsin Lake Rankings
State Parks Near Alexander Lake
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Compare Alexander Lake With Nearby Lakes
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 3 stations on file (most recent sample 2022).
Fish Species (DNR-rated)
Reservoir Info (USACE NID)
Alexander Lake is a man-made reservoir impounded by the Alexander (completed 1913), built primarily for hydroelectric on the Wisconsin River; gravity-type dam, 40 ft tall and 1,481 ft long.
- Surface area
- 803 ac
- Normal storage
- 5,200 ac-ft
- Max storage
- 6,600 ac-ft
- Drainage area
- 2,520 sq mi
- Hazard class
- High
- Owner
- Wisconsin Public Service Corporation
All listed purposes: Hydroelectric;Recreation.
Source: USACE National Inventory of Dams, NID ID WI00748 · Operator website
EPA Impairment Status
Alexander 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 WI10007168 · Official waterbody report · Matched by proximity (2.89 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: 2022-09-21
Monitoring stations: 1