St. Louis County Lake Quality
Missouri, 7 lakes, measured by Missouri DNR
St. Louis County holds 7 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 5 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The monitored lakes here are mostly shallow, productive basins where summer algae is common; each lake page shows its own readings beside the EPA condition class.
Most of the county's monitored lakes are shallow, under 50 feet, which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Simpson Park Lake has the lowest nutrient and algae readings in the county.
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Quick Answers for St. Louis County
Planning a trip? Check special fishing regulations for Simpson Park Lake — or check the official Missouri fishing regulations.
All Lakes in St. Louis County
7 lakes · 5 ranked on readings, 2 without enough sampling5 lakes ranked on readings · 2 without enough sampling, hidden
| # | Lake | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | Simpson Park LakeSt. Louis | 1.9 ft | 72.3 µg/L | 23.8 µg/L | No recent samples | ✓ Public |
| 2 | Mallard LakeSt. Louis | 1.9 ft | 84 µg/L | 32.2 µg/L | No recent samples | Not recorded |
| 3 | Creve Coeur LakeSt. Louis | 1.6 ft | 101 µg/L | 35.4 µg/L | No recent samples | Not recorded |
| 4 | Koeneman Park LakeSt. Louis | 3.1 ft | 270.8 µg/L | 35.9 µg/L | No recent samples | Not recorded |
| 5 | Spanish LakeSt. Louis | 1.6 ft | 347.8 µg/L | 62.6 µg/L | No recent samples | ✓ Public |
| Bee Tree LakeSt. Louis | No recent samples | No recent samples | No recent samples | No recent samples | ✓ Public | |
| Tilles Park ReservoirSt. Louis | No recent samples | 434.5 µg/L | 66.5 µg/L | No recent samples | Not recorded |
NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.
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Source: the Missouri Department of Natural Resources. See data sources.