Caldron Falls Reservoir
Caldron Falls Reservoir in Marinette County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.2 ft visibility. Maximum depth: 40 ft. Surface area: 1063 acres.
- Clarity
- 5.2 ft
- Max depth
- 40 ft
- Area
- 1,063 acres
- Trend
- → Stable
- Public access
- Yes
Next lake in Marinette County
Why Caldron Falls Reservoir has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Caldron Falls Reservoir, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Caldron Falls Reservoir is a 1,063-acre lake in Marinette County, Wisconsin with a maximum depth of 40 feet. The lake supports 5 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 4 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-09-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedBacteria A
Based on E. coli testing, Caldron Falls Reservoir never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 112 samples across 9 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Wisconsin’s current beach and health-department advisories before swimming.
Water quality measurements for Caldron Falls Reservoir
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 5.2 ft. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.2 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Caldron Falls Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Caldron Falls Reservoir in Marinette 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.
Top-rated places to stay near Caldron Falls Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 40 ft |
| Surface Area | 1,063 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Caldron Falls Reservoir #8 - Caldron BayPublic
- Caldron Falls Reservoir #9 - Muskellunge PointPublic
- Caldron Falls Reservoir #13 - South BayPublic
- Caldron Falls Reservoir #10 - North BayPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Caldron Falls Reservoir
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 5 stations on file (most recent sample 2024).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Caldron Falls Reservoir covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2012Caldron Falls Flowage comprehensive fishery survey 2012Comprehensive Survey · WI DNR · 2012 (PDF)
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.062 m/yr | 3 |
Reservoir Info (USACE NID)
Caldron Falls Reservoir is a man-made reservoir impounded by the Caldron Falls (completed 1924), built primarily for hydroelectric on the Peshtigo River; gravity-type dam, 81 ft tall and 1,250 ft long.
- Surface area
- 1,018 ac
- Normal storage
- 11,475 ac-ft
- Max storage
- 11,500 ac-ft
- Drainage area
- 496 sq mi
- Hazard class
- High
- Owner
- Wisconsin Public Service Corporation
All listed purposes: Hydroelectric;Fish and Wildlife Pond;Recreation;Flood Risk Reduction.
Source: USACE National Inventory of Dams, NID ID WI00759 · Operator website
EPA Impairment Status
Caldron Falls Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10001685 · Official waterbody report
Graded lakes near Caldron Falls Reservoir
Caldron Falls Reservoir has no grade, but these lakes within a short drive do.
Nearby Lakes in Marinette County
Frequently asked questions about Caldron Falls Reservoir
What is the water quality grade for Caldron Falls Reservoir?
- Caldron Falls Reservoir in Marinette County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 5.2 ft visibility. Maximum depth: 40 ft. Surface area: 1063 acres.
Is Caldron Falls Reservoir safe to swim in?
- Based on E. coli testing, Caldron Falls Reservoir never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 112 samples across 9 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Caldron Falls Reservoir is not rated for water quality — its monitoring record does not meet the evidence bar. Bacteria levels can spike quickly after heavy rain, so always check Wisconsin's current beach and health-department advisories before you swim.
How deep is Caldron Falls Reservoir?
- Caldron Falls Reservoir has a maximum depth of 40 feet. The lake covers 1063 acres.
What fish are in Caldron Falls Reservoir?
- Fish species found in Caldron Falls Reservoir include Musky, Panfish, Largemouth Bass, Northern Pike, Walleye. Caldron Falls Reservoir is located in Marinette County, Wisconsin.
Are there boat ramps on Caldron Falls Reservoir?
- Caldron Falls Reservoir has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Caldron Falls Reservoir #8 - Caldron Bay, Caldron Falls Reservoir #9 - Muskellunge Point, Caldron Falls Reservoir #13 - South Bay, Caldron Falls Reservoir #10 - North Bay. Public access is listed as yes.
Explore Caldron Falls Reservoir across LakeGrade
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Where this data comes from
7 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX7 samples · 2020–2024
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
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