Rocky River Reservoir
Chatham County, North Carolina100 acresView mapDirections
NC DEQ publishes the water-quality measurements for Rocky River Reservoir. Here is what has been measured.
- Hypereutrophic
- 43 ft max depth
- Limited data
Rocky River Reservoir in Chatham County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 1.9 ft visibility. Phosphorus: 55 µg/L. Chlorophyll-a (algae): 55.5 µg/L. Surface area: 100 acres.
Rocky River Reservoir is a 100-acre highly nutrient-loaded hypereutrophic lake in Chatham County, North Carolina with an estimated average depth of about 43 feet. Compared to the 6 other monitored lakes in Chatham County, Rocky River Reservoir ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, NCDEQ, last sampled 2023-09-21. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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 Rocky River Reservoir 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 Rocky River Reservoir
These are the measurements NC DEQ publishes for Rocky River Reservoir, 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 1.9 ft of visibility. Phosphorus 55 µg/L. Chlorophyll-a 55.5 µg/L. TSI 67.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 55µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 55.5µg/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. | 67 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Rocky River Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~43 ft est.
Surface area
100 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 Rocky River Reservoir.
Lake Size & Watershed
Watershed (drainage) area
35 sq mi
HydroLAKES / HydroSHEDS
Shoreline
5.9 mi
HydroLAKES / HydroSHEDS
Elevation
597 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.
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Stays near Rocky River Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Rocky River Reservoir in Chatham 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 Rocky River Reservoir are listed below.
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Fishing Rocky River Reservoir
Reservoir Info (USACE NID)
Rocky River Reservoir is a man-made reservoir impounded by the Rocky River Reservoir Dam (completed 1961), built primarily for other on the Rocky River; earth-type dam, 30 ft tall and 730 ft long.
- Surface area
- 100 ac
- Normal storage
- 403 ac-ft
- Max storage
- 500 ac-ft
- Drainage area
- 53.8 sq mi
- Hazard class
- Low
- Owner
- Town of Siler City
All listed purposes: Other;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID NC00616 · Operator website
Nearby Lakes in Chatham County
Frequently asked questions about Rocky River Reservoir
Where is Rocky River Reservoir?
- Rocky River Reservoir is a lake in Chatham 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 Rocky River Reservoir?
- Rocky River Reservoir in Chatham County, North Carolina has water-quality measurements published by NC DEQ, shown here as reported. Water clarity: 1.9 ft visibility. Phosphorus: 55 µg/L. Chlorophyll-a (algae): 55.5 µg/L. Surface area: 100 acres.
Is Rocky River Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Rocky River Reservoir?
- No published bathymetric survey covers Rocky River Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 43 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 100 acres.
Explore Rocky River Reservoir across LakeQuality
More lakes in North Carolina
Other Lakes in North Carolina
Hypereutrophic Lakes in North Carolina
Where this data comes from
41 measurements from 2 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Carolina Dept of Environmental Quality NCDEQ-DWR WQX
21NC03WQ41 samples · 2023
Analytical methods
- WSSSOP
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 2130 B ~ Nephelometric Method
Monitoring station identifiers (2)
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)