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C

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.

Reviewed by LakeQuality Editorial Team · Updated

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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.

MetricValueGrade
Water Clarity (Secchi Depth)4 ftD
Phosphorus46.2 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)58Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth36 ft
Surface Area618 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.

Chinese Mystery SnailCurly-Leaf PondweedEurasian Water-MilfoilPurple LoosestrifeRusty Crayfish

Location

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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.

See full comparison →

Nearby Lakes in Lincoln County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 3 stations on file (most recent sample 2022).

Fish Species (DNR-rated)

Largemouth Bass(Common)Smallmouth Bass(Common)Walleye(Common)Musky(Present)Panfish(Present)Northern Pike(Present)

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

Cause unknown

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