Great Gorge Lake
Great Gorge Lake in Sussex County, New Jersey has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 11.1 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Surface area: 23 acres.
- Clarity
- 12.3 ft
- Area
- 23 acres
- Type
- Mesotrophic
Great Gorge Lake is a 23-acre mesotrophic lake in Sussex County, New Jersey. Water quality is graded A based on 2 sampling years through 2024. Compared to the 17 other monitored lakes in Sussex County, Great Gorge Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-07-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyBacteria advisory
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Good clarity, visible to about 12.3 ft. Phosphorus level: 11.1 µg/L. Chlorophyll-a: 3.7 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.3 ft | Not graded |
| Phosphorus | 11.1 µg/L | Good |
| Chlorophyll-a (Algae) | 3.7 µg/L | Good |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Great Gorge Lake
Compare lakeside cabins, hotels, and vacation rentals near Great Gorge Lake in Sussex 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.
Top-rated places to stay near Great Gorge Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 23 acres |
No bathymetric survey has been published for Great Gorge Lake, so its depth is not documented here.
Fishing Great Gorge Lake
Reservoir Info (USACE NID)
Great Gorge Lake is a man-made reservoir impounded by the Great Gorge Dam (completed 1971), built primarily for water supply on the Black River-TR; earth-type dam, 28 ft tall and 160 ft long.
- Surface area
- 23 ac
- Normal storage
- 280 ac-ft
- Max storage
- 290 ac-ft
- Drainage area
- 0.25 sq mi
- Hazard class
- High
- Owner
- Mountain Creek Resort
Source: USACE National Inventory of Dams, NID ID NJ00661 · Operator website
EPA Impairment Status
Great Gorge Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02020007040010-01 · Official waterbody report · Matched by proximity (2.35 km)
County Ranking
Ranked #1 of 18 lakes in Sussex County
Nearby Lakes in Sussex County
Frequently asked questions about Great Gorge Lake
Where is Great Gorge Lake?
- Great Gorge Lake is a lake in Sussex County, New Jersey. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Great Gorge Lake?
- Great Gorge Lake in Sussex County, New Jersey has a water quality grade of A (Excellent). Water clarity: 12.3 ft visibility. Phosphorus: 11.1 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Surface area: 23 acres.
Is Great Gorge Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Great Gorge Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.7 µg/L. Always check local health department advisories before swimming.
Explore Great Gorge Lake across LakeGrade
More New Jersey Lake Rankings
Other Grade A Lakes in New Jersey
Mesotrophic Lakes in New Jersey
Where this data comes from
19 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_BFBM19 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database