Kinmundy Old Lake
Marion County, IllinoisView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- Impaired · Cause unknown
- #5 of 6 in the county
- Limited data
Kinmundy Old Lake in Marion County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 277 µg/L. Chlorophyll-a (algae): 114.8 µg/L.
- Clarity
- 1.5 ft
- Typical in August
- 76°F
- Type
- Hypereutrophic
- Phosphorus
- 277 µg/L
- Chlorophyll-a
- 114.8 µg/L
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Stays near Kinmundy Old Lake
Compare lakeside cabins, hotels, and vacation rentals near Kinmundy Old Lake in Marion County, Illinois — 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 Kinmundy Old Lake are listed below.
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Kinmundy Old Lake is a highly nutrient-loaded hypereutrophic lake in Marion County, Illinois. Water quality is graded F based on 2 sampling years through 2022. Compared to the 5 other monitored lakes in Marion County, Kinmundy Old Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-05. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyLimited data
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.
The F is nutrients and algae, not a swimming clearance. Kinmundy Old Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 1.5 ft of visibility. Phosphorus 277 µg/L. Chlorophyll-a 114.8 µg/L. TSI 78. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | Not graded |
| Phosphorus | 277 µg/L | Poor |
| Chlorophyll-a (Algae) | 114.8 µg/L | Poor |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Kinmundy Old Lake typically sits around 76°F at the surface in August. Summer average is about 74°F. Usually warmest in Aug (about 76°F) and coldest in Apr (about 57°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 160 field readings (2011–2022) via the EPA Water Quality Portal. See the full Kinmundy Old Lake water temperature breakdown →
Fishing Kinmundy Old Lake
Reservoir Info (USACE NID)
Kinmundy Old Lake is a man-made reservoir impounded by the Kinmundy Lake Dam (completed 1885), built primarily for recreation on the TRIB EAST FORK KASKASKIA RIVER; earth-type dam, 25 ft tall and 1,050 ft long.
- Normal storage
- 87 ac-ft
- Max storage
- 121 ac-ft
- Hazard class
- Low
- Owner
- CITY OF KINMUNDY
Source: USACE National Inventory of Dams, NID ID IL00248 · Operator website · Matched by proximity (0.19 km)
EPA Impairment Status
Kinmundy Old Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_ROZY · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Kinmundy Old Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Alma Stp, Village OfAlma · 2.8 mi away · NPDES IL0076422Recent 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 #5 of 6 lakes in Marion County
Nearby Lakes in Marion County
Frequently asked questions about Kinmundy Old Lake
Where is Kinmundy Old Lake?
- Kinmundy Old Lake is a lake in Marion County, Illinois. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Kinmundy Old Lake?
- Kinmundy Old Lake in Marion County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.5 ft visibility. Phosphorus: 277 µg/L. Chlorophyll-a (algae): 114.8 µg/L.
Is Kinmundy Old Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Kinmundy Old Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown. Check local advisories before you swim.
What is the water temperature of Kinmundy Old Lake?
- Kinmundy Old Lake typically sits around 76°F at the surface in August, from 160 EPA Water Quality Portal field readings (2011–2022). That is a typical value for the month, not a live reading.
Explore Kinmundy Old Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Illinois's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
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Where this data comes from
28 measurements from 2 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX28 samples · 2022
Analytical methods
- MEASURED IN FIELD
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (2)
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)