Smithville Dock Lake
Burlington County, New Jersey37 acresView mapDirections
NJDEP publishes the water-quality measurements for Smithville Dock Lake. Here is what has been measured.
- Eutrophic
- Impaired · Metals (other than mercury)
- Limited data
Smithville Dock Lake in Burlington County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
Smithville Dock Lake is a 37-acre productive, nutrient-rich eutrophic lake in Burlington County, New Jersey. 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. Methodology: how these readings are compared.
Swimming conditions
Readings onlyBacteria advisory
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. Smithville Dock Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.
Whether Smithville Dock 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 Smithville Dock Lake
These are the measurements NJDEP publishes for Smithville Dock Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.6 ft of visibility. Phosphorus 90 µg/L. TSI 70.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 90µg/L | Poor GoodFairPoor |
| 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. | 70 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Smithville Dock Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
37 acres
No bathymetric survey has been published for Smithville Dock Lake, so its depth is not documented here.
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Stays 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Smithville Dock Lake are listed below.
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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
Designated uses not supporting: Drinking water, Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02040202040040-01 · Official waterbody report
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. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of Smithville Dock Lake?
- Smithville Dock Lake in Burlington County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 1.6 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
Is Smithville Dock Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Smithville Dock Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.
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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)
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