Boujan Swale Lake
Cass County, IllinoisView mapDirections
Illinois EPA publishes the water-quality measurements for Boujan Swale Lake. Here is what has been measured.
- 101 ft max depth
- Public access
- Limited data
Boujan Swale Lake in Cass County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 136 µg/L.
Boujan Swale Lake is a lake in Cass County, Illinois with an estimated average depth of about 101 feet. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2023-07-18. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Boujan Swale Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Boujan Swale Lake
These are the measurements Illinois EPA publishes for Boujan Swale Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Chlorophyll-a 136 µg/L. TSI 79.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 136µg/L | Measured, not scored 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. | 79 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Boujan Swale Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~101 ft est.
Public access
Yes
Listed by Illinois EPA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Boujan Swale Lake.
Lake Size & Watershed
Watershed (drainage) area
18,066 sq mi
HydroLAKES / HydroSHEDS
Surface area
536 acres
HydroLAKES / HydroSHEDS
Shoreline
7.9 mi
HydroLAKES / HydroSHEDS
Elevation
427 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
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Fishing Boujan Swale Lake
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Boujan Swale 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.
- Beardstown Sd StpBeardstown · 3.5 mi away · NPDES IL0025135MajorRecent violation
- Cargill Meat Solutions CorporationBeardstown · 4.5 mi away · NPDES IL0023914Recent violation
- Osmose Casswood Site-BeardstwnBeardstown · 4.4 mi away · NPDES IL0069299
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.
Nearby Lakes in Cass County
Frequently asked questions about Boujan Swale Lake
Where is Boujan Swale Lake?
- Boujan Swale Lake is a lake in Cass County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Boujan Swale Lake?
- Boujan Swale Lake in Cass County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 136 µg/L.
Is Boujan Swale Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Boujan Swale Lake?
- No published bathymetric survey covers Boujan Swale Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 101 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Can I fish at Boujan Swale Lake?
- Public access to Boujan Swale Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Illinois's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
1 measurement from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Illinois Water Science Center
USGS-IL1 sample · 2023
Analytical methods
- Plant pigments, sonication & 445
Monitoring station identifiers (1)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)