Lake St. Louis by Dam vs Lake St. Louis
Water quality, depth, fish species, and recreation comparison.
Lake St. Louis has a higher water quality grade (D, Poor) than Lake St. Louis by Dam (F, Very Poor). Both are in St. Charles County, Missouri.
Both Lake St. Louis by Dam and Lake St. Louis sit in Missouri. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Lake St. Louis by Dam (F) versus Lake St. Louis (D). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Lake St. Louis by Dam
Very murky, less than 2.3 ft of visibility.
Lake St. Louis
Very murky, less than 2.7 ft of visibility.
Side-by-Side Metrics
| Metric | Lake St. Louis by Dam | Lake St. Louis |
|---|---|---|
| Overall Grade | F (Very Poor) | D (Poor) |
| Water Clarity | 2.3 ft | 2.7 ft |
| Phosphorus | 74.8 µg/L | 50 µg/L |
| Chlorophyll-a (Algae) | 32.2 µg/L | 74.3 µg/L |
| Maximum Depth | - | - |
| Surface Area | 563 acres | 563 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Lake St. Louis wins on overall water quality with a Grade D versus Lake St. Louis by Dam's Grade F. Water clarity: 2.7 ft vs 2.3 ft. For fishing diversity, Lake St. Louis also leads with 0 species.