Dam Lake
Alleghany County, Virginia2,530 acresView mapDirections
Virginia DEQ publishes the water-quality measurements for Dam Lake. Here is what has been measured.
- Oligotrophic
- Public access
Dam Lake in Alleghany County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 12.1 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Surface area: 2530 acres.
Dam Lake is a 2,530-acre cold, clear oligotrophic lake in Alleghany County, Virginia. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 3 public boat landings. Compared to the 1 other monitored lakes in Alleghany County, Dam Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Virginia DEQ, last sampled 2026-07-06. Methodology: how these readings are compared.
What Dam Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.1 ft of visibility
- Boat launch3 documented ramps
- Camping4 public campgrounds nearby
- Big water2,530 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. 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 12.1 ft. Phosphorus 10 µg/L. Chlorophyll-a 1.7 µg/L. TSI 38.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 12.1ft | 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) | 1.7µg/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. | 38 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Dam Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
2,530 acres
Public access
Yes
Listed by Virginia DEQ
No bathymetric survey has been published for Dam Lake, so its depth is not documented here.
Recreation & Access
- Lake Moomaw (Coles Point)Public
- Johnson SpringPublic
- Coles PointPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Dam Lake
- Coles Point0.4 kmReserve
- Morris Hill Group Campground0.4 km
- Greenwood Point Primitive1.3 km
- Morris Hill1.5 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Dam Lake
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Top-rated places to stay near Dam Lake
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Fishing Dam Lake
Water Quality Trend: Improving
Based on 8 years of monitoring (2013–2026).
Water clarity
Stable8 years
Phosphorus
Improving-0.24 µg/L/yr8 years
Chlorophyll-a
Stable-0.01 µg/L/yr8 years
Reservoir Info (USACE NID)
Dam Lake is a man-made reservoir impounded by the Gathright Dam (completed 1978), built primarily for flood risk reduction on the Jackson River; rockfill-type dam, 257 ft tall and 1,208 ft long.
- Surface area
- 2,530 ac
- Normal storage
- 123,700 ac-ft
- Max storage
- 421,500 ac-ft
- Drainage area
- 345 sq mi
- Hazard class
- High
- Owner
- USACE - Norfolk District
All listed purposes: Flood Risk Reduction;Other;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID VA005001 · Operator website · Matched by proximity (0.74 km)
Nearby Lakes in Alleghany County
Frequently asked questions about Dam Lake
Where is Dam Lake?
- Dam Lake is a lake in Alleghany 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 Alleghany County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 12.1 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Surface area: 2530 acres.
Is Dam Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Are there boat ramps on Dam Lake?
- Dam Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Moomaw (Coles Point), Johnson Spring, Coles Point. Public access is listed as yes.
Can I fish at Dam Lake?
- Dam Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Virginia's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Dam Lake?
- Dam Lake has 4 public campgrounds from USGS The National Map within 5 km, including Coles Point, Morris Hill Group Campground, Greenwood Point Primitive, Morris Hill. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Dam Lake across LakeQuality
23.1 mi away · 63 ft
4 thermal springs within 8.1 mi, nearest Falling Spring
Species activity outlook by water temperature and season
Where to stay at Virginia's top lakes, each with its readings
Virginia's cleanest lakes, ranked on agency measurements
More lakes in Virginia
Other Lakes in Virginia
Oligotrophic Lakes in Virginia
Where this data comes from
504 measurements from 1 monitoring station, 2013–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY
21VASWCB504 samples · 2013–2026
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
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles