Koeneman Park Lake
St. Louis County, MissouriView mapDirections
Nutrients and algae run well above the regional average.
- Hypereutrophic
- #4 of 5 in the county
- Limited data
Koeneman Park Lake in St. Louis County, Missouri has a water quality grade of F (Algae-prone). Water clarity: 3.1 ft visibility. Phosphorus: 270.8 µg/L. Chlorophyll-a (algae): 35.9 µg/L.
- Clarity
- 3.1 ft
- Typical in September
- 81°F
- Type
- Hypereutrophic
- Phosphorus
- 270.8 µg/L
- Chlorophyll-a
- 35.9 µg/L
Stays via Stay22
Stays near Koeneman Park Lake
Compare lakeside cabins, hotels, and vacation rentals near Koeneman Park Lake in St. Louis County, Missouri — 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 Koeneman Park Lake are listed below.
Top-rated places to stay near Koeneman Park Lake
Prices for Sep 11–13, 4 adults. Change dates on the map below.
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Koeneman Park Lake is a highly nutrient-loaded hypereutrophic lake in St. Louis County, Missouri. Water quality is graded F based on 2 sampling years through 2020. Compared to the 4 other monitored lakes in St. Louis County, Koeneman Park Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Missouri DNR, last sampled 2020-09-19. 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. Check local advisories before you swim.
Water Quality Grade: F (Algae-prone)
Very murky, less than 3.1 ft of visibility. Phosphorus 270.8 µg/L. Chlorophyll-a 35.9 µg/L. TSI 70. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.1 ft | Not graded |
| Phosphorus | 270.8 µg/L | Poor |
| Chlorophyll-a (Algae) | 35.9 µg/L | Poor |
| Trophic State Index (TSI) | 70 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Water Temperature
Koeneman Park Lake typically sits around 81°F at the surface in September. Summer average is about 84°F. Usually warmest in Jul (about 85°F) and coldest in Apr (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 62 field readings (2010–2020) via the EPA Water Quality Portal. See the full Koeneman Park Lake water temperature breakdown →
Fishing Koeneman Park Lake
Regulated Pollution Sources Nearby
16 EPA-permitted facilities operate within about 5 miles of Koeneman Park Lake under Clean Water Act (NPDES) discharge permits.
- Abf Freight System IncSt Louis · 1.5 mi away · NPDES MONX00891
- City Of Bellefontaine NeighborsSt. Louis · 1.8 mi away · NPDES MONX00332
- Stlco Maintenance District OneFlorissant · 3 mi away · NPDES MONX00330
- Performance Foodservice MiddendorfBerkeley · 3.1 mi away · NPDES MONX01042
- Ups Scs St LouisSt Louis · 4.1 mi away · NPDES MONX00582
- Monarch Advanced SciencesBerkeley · 4.1 mi away · NPDES MONX00819
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 #4 of 5 lakes in St. Louis County
Nearby Lakes With Higher Grades
Koeneman Park Lake holds Grade F. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in St. Louis County
Frequently asked questions about Koeneman Park Lake
Where is Koeneman Park Lake?
- Koeneman Park Lake is a lake in St. Louis County, Missouri. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Koeneman Park Lake?
- Koeneman Park Lake in St. Louis County, Missouri has a water quality grade of F (Algae-prone). Water clarity: 3.1 ft visibility. Phosphorus: 270.8 µg/L. Chlorophyll-a (algae): 35.9 µg/L.
Is Koeneman Park Lake safe to swim in?
- The F is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Koeneman Park Lake?
- Koeneman Park Lake typically sits around 81°F at the surface in September, from 62 EPA Water Quality Portal field readings (2010–2020). That is a typical value for the month, not a live reading.
Explore Koeneman Park Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Missouri's top lakes, each with its grade
Very high nutrients, dense algae, poor clarity
Missouri's cleanest and most-polluted lakes, ranked
Planning a trip around Gateway Arch?
Koeneman Park Lake is about 9 miles from Gateway Arch National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Gateway Arch →More Missouri Lake Rankings
Other Grade F Lakes in Missouri
Hypereutrophic Lakes in Missouri
Where this data comes from
15 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Univ. of Missouri, Columbia
UMC15 samples · 2020
Analytical methods
- Depth, Secchi disk in meters
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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)