Kirk Lake is a 124-acre productive, nutrient-rich eutrophic lake in Putnam County, New York. Water quality is graded D based on 1 sampling years through 2020. Compared to the 12 other monitored lakes in Putnam County, Kirk Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2020-09-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 5 ft. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 124 acres |
Where to stay near Kirk Lake
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Fishing Kirk Lake
Location
County Ranking
Ranked #8 of 13 lakes in Putnam County
Nearby Lakes in Putnam County
Explore Kirk Lake across LakeGrade
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Where to stay at New York's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
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More records, surveys & data sources
Reservoir Info (USACE NID)
Kirk Lake is a man-made reservoir impounded by the Kirk Lake Dam (completed 1871), built primarily for recreation on the TR-MUSCOOT RIVER; earth-type dam, 28 ft tall and 225 ft long.
- Surface area
- 124 ac
- Normal storage
- 1,705 ac-ft
- Max storage
- 1,822 ac-ft
- Drainage area
- 3.1 sq mi
- Hazard class
- Significant
- Owner
- NYCDEP DAMS EAST OF THE HUDSON RIVER
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID NY00682 · Operator website
EPA Impairment Status
Kirk Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NY1302-0080 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
12 EPA-permitted facilities operate within about 5 miles of Kirk Lake under Clean Water Act (NPDES) discharge permits. 4 facilities have a reported Clean Water Act violation in the past three years.
- Putnam National Golf Club WwtpMahopac · 0.8 mi away · NPDES NY0260371Recent violation
- Sclafani Petroleum IncMahopac · 1.5 mi away · NPDES NY0251453Recent violation
- Mahopac (V) StpCarmel · 1.5 mi away · NPDES NY0026590Recent violation
- Enviro Waste Oil Recovery TerminalMahopac · 1.5 mi away · NPDES NY0101753Recent violation
- Carnel Mac Gregor Sewer WorksScarsdale · 0.6 mi away · NPDES NY0219380
- Mahopac School Bus GarageMahopac · 0.9 mi away · NPDES NY0263991
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2020-09-20
Monitoring stations: 1