St Croix Flowage Lake
Douglas County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for St Croix Flowage Lake. Here is what has been measured.
- Mesotrophic
- Public access
- Limited data
St Croix Flowage Lake in Douglas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6.8 ft visibility. Phosphorus: 23.2 µg/L.
St Croix Flowage Lake is a mesotrophic lake in Douglas County, Wisconsin. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 14 other monitored lakes in Douglas County, St Croix Flowage Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2020-09-14. Methodology: how these readings are compared.
What St Croix Flowage Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether St Croix Flowage Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for St Croix Flowage Lake
These are the measurements Wisconsin DNR publishes for St Croix Flowage Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 6.8 ft. Phosphorus 23.2 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 23.2µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about St Croix Flowage Lake
Answers come straight from the public measurements and survey records on this page.
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for St Croix Flowage Lake 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).
- 2009Upper St. Croix Lake Fisheries survey, 2009Fisheries Survey · WI DNR · 2009 (PDF)
Recreation & Access
- North FlowagePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing St Croix Flowage Lake
Nearby Lakes in Douglas County
Frequently asked questions about St Croix Flowage Lake
Where is St Croix Flowage Lake?
- St Croix Flowage Lake is a lake in Douglas County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of St Croix Flowage Lake?
- St Croix Flowage Lake in Douglas County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 6.8 ft visibility. Phosphorus: 23.2 µg/L.
Is St Croix Flowage Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on St Croix Flowage Lake?
- St Croix Flowage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include North Flowage. Public access is listed as yes.
Can I fish at St Croix Flowage Lake?
- St Croix Flowage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore St Croix Flowage Lake across LakeQuality
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Where this data comes from
9 measurements from 2 monitoring stations, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX9 samples · 2020
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Named boat-access points from the USGS National Boat Ramps inventory