Lake Kathryn
Seminole County, FloridaEutrophic
Lake Kathryn is a productive, nutrient-rich eutrophic lake in Seminole County, Florida. Water quality is graded C based on 2 sampling years through 2025. Compared to the 167 other monitored lakes in Seminole County, Lake Kathryn ranks #101 for water quality.
Source: EPA Water Quality Portal sampling records, Florida DNR, last sampled 2025-03-31. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Very murky, less than 3 ft of visibility. Phosphorus level: 25 µg/L. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | D |
| Phosphorus | 25 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #101 of 168 lakes in Seminole County
Cleaner Lakes Within 30 Miles
Lake Kathryn holds Grade C. 5 nearby lakes hold higher grades.
- BLake GriffinSeminole County · 0.6 mi · Higher grade (C → B)
- BLake EllenSeminole County · 0.6 mi · Higher grade (C → B)
- CFairy LakeSeminole County · 0.4 mi · Higher overall water quality score
- CSeminole-Secret LakeSeminole County · 0.7 mi · Higher overall water quality score
- CSeminole-Concord LakeSeminole County · 0.7 mi · Higher overall water quality score
Nearby Lakes in Seminole County
More Florida Lake Rankings
Other Grade C Lakes in Florida
Orange County · Clarity: 3.5 ft
Walton County · Clarity: 4.2 ft
Polk County · Clarity: 3.5 ft
Volusia County · Clarity: 4.5 ft
Walton County · Clarity: 3 ft
Alachua County · Clarity: 3 ft
Eutrophic Lakes in Florida
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-03-31
Monitoring stations: 3
Where to stay near Lake Kathryn
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