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LakeQuality

Spirit River Flowage Lake

D
Grade D — Nutrient-rich
Nutrient-rich · #12 of 13 lakes in the county · 3 ft clear · Eutrophic · 1,220 acres
Eutrophic

Spirit River Flowage Lake in Lincoln County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 49.1 µg/L. Maximum depth: 25 ft. Surface area: 1220 acres.

Wisconsin DNR lists Panfish as common on Spirit River Flowage Lake. DNR survey details →

Clarity
3 ft
Typical in August
73°F
Max depth
25 ft
Area
1,220 acres
Type
Eutrophic
Trend
Improving
Public access
Yes

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Spirit River Flowage Lake

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Spirit River Flowage Lake is a 1,220-acre productive, nutrient-rich eutrophic lake in Lincoln County, Wisconsin with a maximum depth of 25 feet. Water quality is graded D based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 6 public boat landings. Compared to the 12 other monitored lakes in Lincoln County, Spirit River Flowage Lake ranks #12 for water quality.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-29. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Elevated 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

Compare the safest swimming lakes near Rhinelander

Get alerts for Spirit River Flowage Lake

Water Quality Grade: D (Nutrient-rich)

Very murky, less than 3 ft of visibility. Phosphorus level: 49.1 µg/L. Trophic State Index: 61.

MetricValueGrade
Water Clarity (Secchi Depth)3 ftNot graded
Phosphorus49.1 µg/LPoor
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)61Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Spirit River Flowage Lake

Compare lakeside cabins, hotels, and vacation rentals near Spirit River Flowage Lake in Lincoln 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 Spirit River Flowage Lake are listed below.

Top-rated places to stay near Spirit River Flowage Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a trip? Cabins and lodging at Spirit River Flowage Lake · more Wisconsin lake trips

Water Temperature

Spirit River Flowage Lake typically sits around 73°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 82°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
63°
Jun
69°
Jul
82°
Aug
73°
Sep
Oct
Nov
Dec

Typical surface water temperature by month, from 13 field readings (20242026) via the EPA Water Quality Portal. See the full Spirit River Flowage Lake water temperature breakdown →

DNR fisheries survey

Wisconsin DNR lists Panfish as common on Spirit River Flowage Lake.

A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Spirit River Flowage Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. 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 2007. 4 stations on file (most recent sample 2025).

Fish Species (DNR-rated)

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

Lake Details

CharacteristicValue
Maximum Depth25 ft
Surface Area1,220 acres
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
163 sq mi
Shoreline
17.2 mi
Elevation
1,430 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

6
Boat Landings
Yes
Public Access
  • Spirit River Flowage - 2Public
  • Wisconsin River - Park LanePublic
  • Wisconsin River - Herb Mitchell RoadPublic
  • Lake MohawksinSemi-private
  • Spirit Flowage - 1Semi-private
  • Wisconsin RiverSemi-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 Spirit River 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.

Purple LoosestrifeRusty Crayfish

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.539 m/yr6
Phosphorus Improving-4.86 µg/L/yr6
See year-by-year chart →

Reservoir Info (USACE NID)

Spirit River Flowage Lake is a man-made reservoir impounded by the Spirit (completed 1922), built primarily for hydroelectric on the Spirit River; gravity-type dam, 26 ft tall and 2,530 ft long.

Surface area
1,698 ac
Max storage
15,427 ac-ft
Drainage area
158 sq mi
Hazard class
High
Owner
Wisconsin Valley Improvement Company

All listed purposes: Hydroelectric;Flood Risk Reduction.

Source: USACE National Inventory of Dams, NID ID WI00749 · Operator website · Matched by proximity (0.51 km)

EPA Impairment Status

Spirit River 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

MercuryNutrients (phosphorus, nitrogen)

Source: EPA ATTAINS assessment unit WI10007188 · Official waterbody report

Regulated Pollution Sources Nearby

2 EPA-permitted facilities operate within about 5 miles of Spirit River Flowage Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.

  • Packaging Corp Of America
    Lincoln County · 0.4 mi away · NPDES WI0002810
    MajorRecent violation
  • Tomahawk City Of
    Bradley · 1.8 mi away · NPDES WI0021946
    Recent 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 #12 of 13 lakes in Lincoln County

Nearby Lakes With Higher Grades

Spirit River 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 Lincoln County

Frequently asked questions about Spirit River Flowage Lake

Where is Spirit River Flowage Lake?

Spirit River Flowage Lake is a lake in Lincoln County, Wisconsin. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Spirit River Flowage Lake?

Spirit River Flowage Lake in Lincoln County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 49.1 µg/L. Maximum depth: 25 ft. Surface area: 1220 acres.

Is Spirit River 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. Spirit River 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 Spirit River Flowage Lake?

Spirit River Flowage Lake typically sits around 73°F at the surface in August, from 13 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.

How deep is Spirit River Flowage Lake?

Spirit River Flowage Lake has a maximum depth of 25 feet. The lake covers 1220 acres.

What fish are in Spirit River Flowage Lake?

Fish species found in Spirit River Flowage Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Spirit River Flowage Lake is located in Lincoln County, Wisconsin.

What did the DNR fisheries survey find at Spirit River Flowage Lake?

Wisconsin DNR lists Panfish as common on Spirit River Flowage Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Spirit River Flowage Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.

Are there boat ramps on Spirit River Flowage Lake?

Spirit River Flowage Lake has 6 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Spirit River Flowage - 2, Wisconsin River - Park Lane, Wisconsin River - Herb Mitchell Road, Lake Mohawksin, among others. Public access is listed as yes.

State Parks Near Spirit River Flowage Lake

Where this data comes from

55 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 ResourcesWIDNR_WQX55 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