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F

Forestville Millpond

Door County, WisconsinEutrophic

Forestville Millpond earns an F: 94 µg/L of phosphorus and clarity at 3.0 ft signal heavy nutrient loading from the surrounding watershed. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. A maximum depth of just 5 ft means sediment-bound phosphorus releases back into the water column whenever wind stirs the bottom — a classic shallow-lake dynamic. At 65 acres, Forestville Millpond sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within the 11 graded lakes of Door County, Forestville Millpond sits at rank 11, near the bottom of the county list.

Eurasian watermilfoil has been documented at Forestville Millpond, requiring shoreline management to keep dense mats from crowding native vegetation. The fishery is bass-led, with 4 documented species across the lake's records. 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 2023-08-16. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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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 3 ft of visibility. Phosphorus level: 94.3 µg/L. Trophic State Index: 66.

MetricValueGrade
Water Clarity (Secchi Depth)3 ftF
Phosphorus94.3 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)66Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth5 ft
Surface Area65 acres

Fish Species

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

→ Best fishing times for Forestville Millpond (14-day solunar calendar)

→ Is it safe to eat fish from Forestville Millpond? (mercury & PFAS guide)

Forestville Millpond 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.

Curly-Leaf PondweedEurasian Water-Milfoil

Water Quality Trend: Declining

Based on 4 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.449 m/yr4
See year-by-year chart →

Location

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County Ranking

Ranked #11 of 11 lakes in Door County

Cleaner Lakes Within 30 Miles

Forestville Millpond holds Grade F. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Door County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2005. 3 stations on file (most recent sample 2025).

Fish Species (DNR-rated)

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

DNR Reports & Resources

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

Reservoir Info (USACE NID)

Forestville Millpond is a man-made reservoir impounded by the Forestville (completed 1877), built primarily for recreation on the AHNAPEE RIVER; earth-type dam, 10 ft tall and 1,200 ft long.

Surface area
72 ac
Normal storage
170 ac-ft
Max storage
300 ac-ft
Drainage area
31 sq mi
Hazard class
Low
Owner
Door County

Source: USACE National Inventory of Dams, NID ID WI00256 · Operator website · Matched by proximity (0.06 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2023-08-16

Monitoring stations: 1