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LakeQuality
B

Apple River Flowage Lake

Polk County, WisconsinEutrophic

On the LakeGrade scale Apple River Flowage Lake grades a B, with clarity at 18.0 ft and 79 µg/L of phosphorus placing it above the Wisconsin median. Of the three parameters, phosphorus is the worst — at 79 µg/L of phosphorus, it keeps the lake susceptible to algal blooms in warm years.

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. Apple River Flowage Lake reaches 18 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Apple River Flowage Lake covers 604 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within the 77 graded lakes of Polk County, Apple River Flowage Lake sits at rank 59, near the bottom of the county list.

An invasive species record — Chinese Mystery Snail — has been logged at Apple River Flowage Lake; Wisconsin DNR maintains the official infested-waters list. Bass fishing is part of the appeal: the species list runs to 4, anchored by largemouth and/or smallmouth bass. 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 2025-10-08. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Crystal clear, you can see 18 ft down. Phosphorus level: 78.5 µg/L. Trophic State Index: 51.

MetricValueGrade
Water Clarity (Secchi Depth)18 ftA
Phosphorus78.5 µg/LD
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)51Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth18 ft
Surface Area604 acres
Public AccessYes

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Apple River Flowage Lake (14-day solunar calendar)

→ Is it safe to eat fish from Apple River Flowage Lake? (mercury & PFAS guide)

Apple River Flowage Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Chinese Mystery SnailCurly-Leaf PondweedPurple Loosestrife

Water Quality Trend: Improving

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.079 m/yr6
Phosphorus Improving-15.92 µg/L/yr4
See year-by-year chart →

Recreation & Access

3
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #59 of 77 lakes in Polk County

Cleaner Lakes Within 30 Miles

Apple River Flowage Lake holds Grade B. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Polk County

Eutrophic Lakes in Wisconsin

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1986. 3 stations on file (most recent sample 2025).

Fish Species (DNR-rated)

Panfish(Abundant)Musky(Common)Largemouth Bass(Common)Northern Pike(Common)

DNR Reports & Resources

Wisconsin DNR Fisheries scientists publish multi-year survey reports for Apple River Flowage Lake covering fish populations, stocking, water quality, and management. 1 report on file.

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

Most recent sample: 2025-10-08

Monitoring stations: 1