Big Lake
Wake County, North Carolina25 acresView mapDirections
NC DEQ publishes the water-quality measurements for Big Lake. Here is what has been measured.
- Hypereutrophic
- 24 ft max depth
Big Lake in Wake County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 37 µg/L. Surface area: 25 acres.
Big Lake is a 25-acre highly nutrient-loaded hypereutrophic lake in Wake County, North Carolina with an estimated average depth of about 24 feet. Overall water quality is improving over recent sampling years. Compared to the 13 other monitored lakes in Wake County, Big Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, NCDEQ, last sampled 2025-09-04. Methodology: how these readings are compared.
Swimming conditions
Readings onlyAlgae risk
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. Check local advisories before you swim.
Whether Big Lake is safe to swim in today is a call for the North Carolina Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Lake
These are the measurements NC DEQ publishes for Big 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 2.3 ft of visibility. Phosphorus 50 µg/L. Chlorophyll-a 37 µg/L. TSI 64.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.3ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 50µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 37µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 64 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Big Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~24 ft est.
Surface area
25 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. North Carolina has not published bathymetry for Big Lake.
Lake Size & Watershed
Watershed (drainage) area
7 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.6 mi
HydroLAKES / HydroSHEDS
Elevation
361 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Big Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Lake in Wake County, North Carolina — 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 Big Lake are listed below.
Top-rated places to stay near Big Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at North Carolina’s top lakes →
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Fishing Big Lake
Water quality readings over time
2 seasons of samples on record (2020–2025). Calling a direction takes at least 4 years of the same measurement.
Phosphorus
Improving-2 µg/L/yr2 years
Chlorophyll-a
Stable-0.5 µg/L/yr2 years
Reservoir Info (USACE NID)
Big Lake is a man-made reservoir impounded by the Umstead Park Lake Dam #1 (completed 1940), built primarily for recreation on the Sycamore Creek; earth-type dam, 30 ft tall and 410 ft long.
- Surface area
- 25 ac
- Normal storage
- 360 ac-ft
- Max storage
- 432 ac-ft
- Drainage area
- 7.11 sq mi
- Hazard class
- Low
- Owner
- NC Department of Natural and Cultural Resources
Source: USACE National Inventory of Dams, NID ID NC00881 · Operator website
Nearby Lakes in Wake County
Frequently asked questions about Big Lake
Where is Big Lake?
- Big Lake is a lake in Wake County, North Carolina. Its water-quality measurements are published by NC DEQ and shown on this page as reported.
What is the water quality of Big Lake?
- Big Lake in Wake County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 2.3 ft visibility. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 37 µg/L. Surface area: 25 acres.
Is Big Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Big Lake?
- No published bathymetric survey covers Big Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 24 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 25 acres.
Explore Big Lake across LakeQuality
More lakes in North Carolina
Other Lakes in North Carolina
Hypereutrophic Lakes in North Carolina
Where this data comes from
35 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Carolina Dept of Environmental Quality NCDEQ-DWR WQX
21NC03WQ35 samples · 2020–2025
Analytical methods
- WSSSOP
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric 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
Lake size & watershed from HydroLAKES (HydroSHEDS)