Dam Lake
Pittsylvania County, Virginia20,400 acresView mapDirections
Virginia DEQ publishes the water-quality measurements for Dam Lake. Here is what has been measured.
- Mesotrophic
- Impaired · PCBs
Dam Lake in Pittsylvania County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 10.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2 µg/L. Surface area: 20400 acres.
Dam Lake is a 20,400-acre mesotrophic lake in Pittsylvania County, Virginia. Overall water quality is improving over recent sampling years. Compared to the 2 other monitored lakes in Pittsylvania County, Dam Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Virginia DEQ, last sampled 2026-06-10. Methodology: how these readings are compared.
What Dam Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.5 ft of visibility
- Big water20,400 acres
Swimming conditions
Readings onlyLow algae
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. Dam Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for pCBs. Check local advisories before you swim.
Whether Dam Lake is safe to swim in today is a call for the Virginia Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Dam Lake
These are the measurements Virginia DEQ publishes for Dam Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10.5 ft. Phosphorus 10 µg/L. Chlorophyll-a 2 µg/L. TSI 39.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 10µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 2µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 39 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Dam Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
20,400 acres
No bathymetric survey has been published for Dam Lake, so its depth is not documented here.
Stays via Stay22
Stays near Dam Lake
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Fishing Dam Lake
Water Quality Trend: Improving
Based on 15 years of monitoring (2012–2026).
Water clarity
Stable15 years
Phosphorus
Improving-0.37 µg/L/yr15 years
Chlorophyll-a
Stable+0.02 µg/L/yr15 years
Reservoir Info (USACE NID)
Dam Lake is a man-made reservoir impounded by the Smith Mountain Combination Pump Storage (completed 1964), built primarily for hydroelectric on the Roanoke; arch-type dam, 237 ft tall and 816 ft long.
- Surface area
- 20,400 ac
- Normal storage
- 1,150,000 ac-ft
- Max storage
- 1,150,000 ac-ft
- Drainage area
- 1,024 sq mi
- Hazard class
- High
- Owner
- Appalachian Power Company
Source: USACE National Inventory of Dams, NID ID VA019002 · Operator website · Matched by proximity (0.61 km)
EPA Impairment Status
Dam Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit VAW-L12L_ROA01A02 · Official waterbody report
Nearby Lakes in Pittsylvania County
Frequently asked questions about Dam Lake
Where is Dam Lake?
- Dam Lake is a lake in Pittsylvania County, Virginia. Its water-quality measurements are published by Virginia DEQ and shown on this page as reported.
What is the water quality of Dam Lake?
- Dam Lake in Pittsylvania County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 10.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2 µg/L. Surface area: 20400 acres.
Is Dam Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Dam Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for pCBs. Check local advisories before you swim.
Explore Dam Lake across LakeQuality
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Where this data comes from
691 measurements from 1 monitoring station, 2012–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY
21VASWCB691 samples · 2012–2026
Analytical methods
- Tyler, John. 1968. The secchi disk, Limnology and Oceanograpy, 13(1):1-6.
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- 446.0 ~ EPA; Chlorophylls and Pheopigments in Phytoplankton by Spectrophotometry
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