Lake Alcyon
Gloucester County, New Jersey19 acresView mapDirections
NJDEP publishes the water-quality measurements for Lake Alcyon. Here is what has been measured.
- Impaired · Mercury
- Limited data
Lake Alcyon in Gloucester County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 4.3 ft visibility. Surface area: 19 acres.
Lake Alcyon is a 19-acre lake in Gloucester County, New Jersey.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-10-21. Methodology: how these readings are compared.
Swimming conditions
No readingBacteria advisory
Nutrient and algae readings are not a swimming clearance. Lake Alcyon is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal). Check local advisories before you swim.
Whether Lake Alcyon 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 Lake Alcyon
These are the measurements NJDEP publishes for Lake Alcyon, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.3 ft. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Alcyon
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
19 acres
No bathymetric survey has been published for Lake Alcyon, so its depth is not documented here.
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Fishing Lake Alcyon
Reservoir Info (USACE NID)
Lake Alcyon is a man-made reservoir impounded by the Alcyon Lake Dam (completed 1943), built primarily for recreation on the Chestnut Branch Mantua Creek; earth-type dam, 12 ft tall and 480 ft long.
- Surface area
- 19 ac
- Normal storage
- 66 ac-ft
- Max storage
- 150 ac-ft
- Drainage area
- 4 sq mi
- Hazard class
- Significant
- Owner
- Borough of Pitman
Source: USACE National Inventory of Dams, NID ID NJ00427 · Operator website
EPA Impairment Status
Lake Alcyon 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, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02040202130030-01 · Official waterbody report
Nearby Lakes in Gloucester County
Frequently asked questions about Lake Alcyon
Where is Lake Alcyon?
- Lake Alcyon is a lake in Gloucester County, New Jersey. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of Lake Alcyon?
- Lake Alcyon in Gloucester County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 4.3 ft visibility. Surface area: 19 acres.
Is Lake Alcyon safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Alcyon is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal). Check local advisories before you swim.
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Where this data comes from
6 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Princeton Hydro LLC
PRINCETONHYDRO6 samples · 2024–2025
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