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.
Track Forestville Millpond
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
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.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | F |
| Phosphorus | 94.3 µg/L | F |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 5 ft |
| Surface Area | 65 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.
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.449 m/yr | 4 |
Location
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.
- AClark LakeDoor County · mi · Two grade letters higher (F → A)
- BKrohns LakeKewaunee County · mi · Two grade letters higher (F → B)
- BEast Alaska LakeKewaunee County · mi · Two grade letters higher (F → B)
- BWest Alaska LakeKewaunee County · mi · Two grade letters higher (F → B)
- CDunes LakeDoor County · mi · Two grade letters higher (F → C)
Nearby Lakes in Door County
More Wisconsin Lake Rankings
State Parks Near Forestville Millpond
Other Grade F Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
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)
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.
- 2024Forestville Millpond spring shocking survey, 2024Spring Shocking Survey · WI DNR · 2024 (PDF)
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