Green Turtle Lake
Passaic County, New Jersey28 acresView mapDirections
NJDEP publishes the water-quality measurements for Green Turtle Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- Limited data
Green Turtle Lake in Passaic County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 13.9 µg/L. Chlorophyll-a (algae): 16.1 µg/L. Surface area: 28 acres.
Green Turtle Lake is a 28-acre productive, nutrient-rich eutrophic lake in Passaic County, New Jersey. Compared to the 5 other monitored lakes in Passaic County, Green Turtle Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-07-31. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Green Turtle Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pH / acidity, temperature. Check local advisories before you swim.
Whether Green Turtle Lake is safe to swim in today is a call for the New Jersey Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Green Turtle Lake
These are the measurements NJDEP publishes for Green Turtle Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.2 ft. Phosphorus 13.9 µg/L. Chlorophyll-a 16.1 µg/L. TSI 50.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13.9µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 16.1µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 50 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Green Turtle Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
28 acres
No bathymetric survey has been published for Green Turtle Lake, so its depth is not documented here.
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Stays near Green Turtle Lake
Compare lakeside cabins, hotels, and vacation rentals near Green Turtle Lake in Passaic County, New Jersey — 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Green Turtle Lake are listed below.
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Fishing Green Turtle Lake
Reservoir Info (USACE NID)
Green Turtle Lake is a man-made reservoir impounded by the Green Turtle Pond Dam, built primarily for recreation on the Wanaque River-TR; earth-type dam, 35 ft tall and 305 ft long.
- Surface area
- 28 ac
- Normal storage
- 251 ac-ft
- Drainage area
- 0.5 sq mi
- Hazard class
- High
- Owner
- Division of Parks and Forestry
Source: USACE National Inventory of Dams, NID ID NJ00190 · Operator website
EPA Impairment Status
Green Turtle Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02030103070030-01 · Official waterbody report
Nearby Lakes in Passaic County
Frequently asked questions about Green Turtle Lake
Where is Green Turtle Lake?
- Green Turtle Lake is a lake in Passaic County, New Jersey. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of Green Turtle Lake?
- Green Turtle Lake in Passaic County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 7.2 ft visibility. Phosphorus: 13.9 µg/L. Chlorophyll-a (algae): 16.1 µg/L. Surface area: 28 acres.
Is Green Turtle Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Green Turtle Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pH / acidity, temperature. Check local advisories before you swim.
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Where this data comes from
18 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- NJDEP Bureau of Freshwater and Biological Monitoring
NJDEP_BFBM18 samples · 2021–2024
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database