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LakeQuality
C

Amherst Millpond

Portage County, WisconsinLimited DataEutrophic

Amherst Millpond sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. At only 7 ft deep, Amherst Millpond is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. Amherst Millpond is small — 38 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Amherst Millpond ranks 22 of 28 in Portage County — at the lower end of the locally monitored distribution.

An invasive species record — Banded Mystery Snail — has been logged at Amherst Millpond; Wisconsin DNR maintains the official infested-waters list. The lake's fish records list 2 species — a varied community without one dominant gamefish. 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 2021-08-22. Grade methodology: LakeGrade methodology.

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Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

No clarity data. Phosphorus level: 31.3 µg/L. Trophic State Index: 54.

MetricValueGrade
Water Clarity (Secchi Depth)No data
Phosphorus31.3 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)54Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth7 ft
Surface Area38 acres
Public AccessYes

Fish Species

Click a species to see every graded lake where it is documented.

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

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

Amherst 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.

Banded Mystery SnailCurly-Leaf PondweedJapanese knotweedPurple LoosestrifeRusty Crayfish

Water Quality Trend: Improving

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Phosphorus Improving-2.6 µg/L/yr2

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #22 of 28 lakes in Portage County

Cleaner Lakes Within 30 Miles

Amherst Millpond holds Grade C. 3 nearby lakes hold higher grades.

Nearby Lakes in Portage County

State Parks Near Amherst Millpond

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 4 stations on file (most recent sample 2021).

Fish Species (DNR-rated)

Panfish(Common)Northern Pike(Present)

Reservoir Info (USACE NID)

Amherst Millpond is a man-made reservoir impounded by the Amherst (completed 1857), built primarily for recreation on the Waupaca (Tomorrow) River; gravity-type dam, 14 ft tall and 370 ft long.

Surface area
48 ac
Normal storage
116 ac-ft
Max storage
260 ac-ft
Drainage area
90 sq mi
Hazard class
Significant
Owner
Renew Hydro Power, LLC;Village of Amherst

All listed purposes: Recreation;Hydroelectric.

Source: USACE National Inventory of Dams, NID ID WI00286 · Operator website · Matched by proximity (0.66 km)

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

Public boat-access points from the USGS National Boat Ramps inventory

Most recent sample: 2021-08-22

Monitoring stations: 1

Where to stay near Amherst Millpond

Compare lakeside cabins, hotels, and vacation rentals near Amherst Millpond in Portage County, Wisconsin — live availability and prices for your trip.

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