Smithville Mid-Lake
Smithville Mid-Lake in Burlington County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.7 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
- Clarity
- 0.7 ft
- Area
- 37 acres
Why Smithville Mid-Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Smithville Mid-Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity and phosphorus, but not algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by your state environmental agency and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Smithville Mid-Lake is a 37-acre lake in Burlington County, New Jersey.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-06-17. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedBacteria advisory
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Smithville Mid-Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 0.7 ft of visibility. Phosphorus level: 90 µg/L. Trophic State Index: 76.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.7 ft | Not graded |
| Phosphorus | 90 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 76 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Smithville Mid-Lake
Compare lakeside cabins, hotels, and vacation rentals near Smithville Mid-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.
Top-rated places to stay near Smithville Mid-Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 37 acres |
No bathymetric survey has been published for Smithville Mid-Lake, so its depth is not documented here.
Fishing Smithville Mid-Lake
Reservoir Info (USACE NID)
Smithville Mid-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 (0.21 km)
EPA Impairment Status
Smithville Mid-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 (2.24 km)
Graded lakes near Smithville Mid-Lake
Smithville Mid-Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Burlington County
Frequently asked questions about Smithville Mid-Lake
Where is Smithville Mid-Lake?
- Smithville Mid-Lake is a lake in Burlington County, New Jersey. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Smithville Mid-Lake?
- Smithville Mid-Lake in Burlington County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 0.7 ft visibility. Phosphorus: 90 µg/L. Surface area: 37 acres.
Is Smithville Mid-Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Smithville Mid-Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Smithville Mid-Lake across LakeGrade
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Hypereutrophic Lakes in New Jersey
Where this data comes from
2 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
PRINCETONHYDRO2 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