Boujan Swale Lake
Cass County, IllinoisView mapDirections
Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.
- 101 ft max depth
- Public access
- Limited data
Boujan Swale Lake in Cass County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Chlorophyll-a (algae): 136 µg/L.
- Max depth
- ~101 ft est.
- Chlorophyll-a
- 136 µg/L
- Public access
- Yes
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Watch Boujan Swale Lake’s letter
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Why Boujan Swale Lake has no grade
We grade a lake only when the monitoring record supports a letter: 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 Boujan Swale Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded algae (chlorophyll-a), but not water clarity and phosphorus.
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 Illinois EPA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Boujan Swale Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Chlorophyll-a 136 µg/L. TSI 79.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 136 µg/L | Not graded |
| Trophic State Index (TSI) | 79 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~101 ft est. |
| Average Depth | ~3 ft est. |
| Public Access | Yes |
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
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.
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.
Graded lakes near Boujan Swale Lake
Boujan Swale Lake has no grade, but these lakes within a short drive do.
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. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Boujan Swale Lake?
- Boujan Swale Lake in Cass County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Chlorophyll-a (algae): 136 µg/L.
Is Boujan Swale Lake safe to swim in?
- The letter is 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.
Explore Boujan Swale Lake across LakeQuality
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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)
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)