Petenwell Flowage Lake
Petenwell Flowage Lake in Juneau County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 81.7 µg/L. Maximum depth: 44 ft. Surface area: 23173 acres.
Wisconsin DNR lists Panfish as common on Petenwell Flowage Lake. DNR survey details →
- Clarity
- 2.3 ft
- Typical in August
- 74°F
- Max depth
- 44 ft
- Area
- 23,173 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Petenwell Flowage Lake →
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Petenwell Flowage Lake is a 23,173-acre productive, nutrient-rich eutrophic lake in Juneau County, Wisconsin with a maximum depth of 44 feet. Water quality is graded D based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. The lake supports 8 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 5 public boat landings. Compared to the 1 other monitored lakes in Juneau County, Petenwell Flowage Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-20. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyElevated nutrients
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.3 ft of visibility. Phosphorus level: 81.7 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.3 ft | Not graded |
| Phosphorus | 81.7 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Petenwell Flowage Lake
Compare lakeside cabins, hotels, and vacation rentals near Petenwell Flowage Lake in Juneau County, Wisconsin — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Petenwell Flowage Lake are listed below.
Top-rated places to stay near Petenwell Flowage Lake
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Planning a trip? Cabins and lodging at Petenwell Flowage Lake → · more Wisconsin lake trips
Water Temperature
Petenwell Flowage Lake typically sits around 74°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 79°F) and coldest in Apr (about 68°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 8 field readings (2025–2026) via the EPA Water Quality Portal. See the full Petenwell Flowage Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Petenwell Flowage Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was very high (1,584,893 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Wisconsin DNR lists Panfish as common on Petenwell Flowage Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Petenwell Flowage Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2005. 60 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 44 ft |
| Surface Area | 23,173 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Petenwell Wilderness ParkPublic
- Petenwell County ParkPublic
- Monroe ParkPublic
- Petenwell Park - 20th DrivePublic
- Barnum BaySemi-private
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Petenwell Flowage Lake
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 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.038 m/yr | 6 |
| Phosphorus | ↓ Declining | +4.76 µg/L/yr | 5 |
EPA Impairment Status
Petenwell Flowage Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10008638 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Petenwell Flowage Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Central Sands Dairy LlcArmenia, Town Of · 4.4 mi away · NPDES WI0063533Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #1 of 2 lakes in Juneau County
Nearby Lakes With Higher Grades
Petenwell Flowage Lake holds Grade D. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Juneau County
Frequently asked questions about Petenwell Flowage Lake
Where is Petenwell Flowage Lake?
- Petenwell Flowage Lake is a lake in Juneau County, Wisconsin. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Petenwell Flowage Lake?
- Petenwell Flowage Lake in Juneau County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 2.3 ft visibility. Phosphorus: 81.7 µg/L. Maximum depth: 44 ft. Surface area: 23173 acres.
Is Petenwell Flowage Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Petenwell Flowage Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
What is the water temperature of Petenwell Flowage Lake?
- Petenwell Flowage Lake typically sits around 74°F at the surface in August, from 8 EPA Water Quality Portal field readings (2025–2026). That is a typical value for the month, not a live reading.
How deep is Petenwell Flowage Lake?
- Petenwell Flowage Lake has a maximum depth of 44 feet. The lake covers 23173 acres.
What fish are in Petenwell Flowage Lake?
- Fish species found in Petenwell Flowage Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye, Sturgeon, Catfish. Petenwell Flowage Lake is located in Juneau County, Wisconsin.
What did the DNR fisheries survey find at Petenwell Flowage Lake?
- Wisconsin DNR lists Panfish as common on Petenwell Flowage Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Petenwell Flowage Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Does Petenwell Flowage Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Petenwell Flowage Lake (clouds, ice, or an off-season gap). The most recent reading was very high (1,584,893 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Petenwell Flowage Lake?
- Petenwell Flowage Lake has 5 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Petenwell Wilderness Park, Petenwell County Park, Monroe Park, Petenwell Park - 20th Drive, among others. Public access is listed as yes.
Explore Petenwell Flowage Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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State Parks Near Petenwell Flowage Lake
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Eutrophic Lakes in Wisconsin
Where this data comes from
67 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX67 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory