Smithville Dock Lake
Smithville Dock Lake in Burlington County, New Jersey has a water quality grade of D (Nutrient-rich). Water clarity: 1.6 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
- Clarity
- 1.6 ft
- Area
- 37 acres
- Type
- Eutrophic
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Smithville Dock Lake →
Smithville Dock Lake is a 37-acre productive, nutrient-rich eutrophic lake in Burlington County, New Jersey. Water quality is graded D based on 1 sampling years through 2025. Compared to the 11 other monitored lakes in Burlington County, Smithville Dock Lake ranks #10 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-10-18. 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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 1.6 ft of visibility. Phosphorus level: 90 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | Not graded |
| Phosphorus | 90 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 70 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Smithville Dock Lake
Compare lakeside cabins, hotels, and vacation rentals near Smithville Dock Lake in Burlington 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 grade measures nutrients and algae, not lodging — cabins and rentals around Smithville Dock Lake are listed below.
Top-rated places to stay near Smithville Dock Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 37 acres |
No bathymetric survey has been published for Smithville Dock Lake, so its depth is not documented here.
Fishing Smithville Dock Lake
Reservoir Info (USACE NID)
Smithville Dock Lake is a man-made reservoir impounded by the Smithville Dam (completed 1935), built primarily for recreation on the North Branch Rancocas Creek; timber crib-type dam, 10 ft tall and 60 ft long.
- Surface area
- 37 ac
- Normal storage
- 65 ac-ft
- Max storage
- 244 ac-ft
- Drainage area
- 132 sq mi
- Hazard class
- High
- Owner
- County of Burlington
Source: USACE National Inventory of Dams, NID ID NJ00043 · Operator website · Matched by proximity (0.23 km)
EPA Impairment Status
Smithville Dock 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 NJ02040202040040-01 · Official waterbody report · Matched by proximity (2.14 km)
County Ranking
Ranked #10 of 12 lakes in Burlington County
Nearby Lakes in Burlington County
Frequently asked questions about Smithville Dock Lake
Where is Smithville Dock Lake?
- Smithville Dock Lake is a lake in Burlington County, New Jersey. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Smithville Dock Lake?
- Smithville Dock Lake in Burlington County, New Jersey has a water quality grade of D (Nutrient-rich). Water clarity: 1.6 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
Is Smithville Dock Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Smithville Dock Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
Explore Smithville Dock Lake across LakeGrade
More New Jersey Lake Rankings
Other Grade D Lakes in New Jersey
Eutrophic Lakes in New Jersey
Where this data comes from
9 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
PRINCETONHYDRO9 samples · 2024–2025
Analytical methods
- 4500 P B ~ Phosphorus, sample preparation method
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