Dam Lake
Alleghany County, Virginia2,530 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Oligotrophic
- #1 of 2 in the county
- Public access
Dam Lake in Alleghany County, Virginia has a water quality grade of A (Excellent). Water clarity: 12.1 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Surface area: 2530 acres.
- Clarity
- 12.1 ft
- Area
- 2,530 acres
- Type
- Oligotrophic
- Phosphorus
- 10 µg/L
- Chlorophyll-a
- 1.7 µg/L
- Trend
- ↑ Improving
- Public access
- Yes
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Dam Lake is a 2,530-acre cold, clear oligotrophic lake in Alleghany County, Virginia. Water quality is graded A based on 2 sampling years through 2026. 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. Grade methodology: LakeQuality methodology.
What Dam Lake is good for
From access and monitoring records, not editorial picks.
- Clear water12.1 ft of visibility
- Boat launch3 documented ramps
- Camping3 public campgrounds nearby
- Big water2,530 acres
Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The A is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Good clarity, visible to about 12.1 ft. Phosphorus 10 µg/L. Chlorophyll-a 1.7 µg/L. TSI 38. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.1 ft | Not graded |
| Phosphorus | 10 µg/L | Good |
| Chlorophyll-a (Algae) | 1.7 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 2,530 acres |
| Public Access | Yes |
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
- 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
Fishing Dam Lake
Water Quality Trend: ↑ Improving
Based on 8 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.002 m/yr | 8 |
| Phosphorus | ↑ Improving | -0.24 µg/L/yr | 8 |
| Chlorophyll-a | → Stable | -0.01 µg/L/yr | 8 |
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)
County Ranking
Ranked #1 of 2 lakes in Alleghany County
Nearby Lakes in Alleghany County
Frequently asked questions about Dam Lake
Where is Dam Lake?
- Dam Lake is a lake in Alleghany County, Virginia. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Dam Lake?
- Dam Lake in Alleghany County, Virginia has a water quality grade of A (Excellent). 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?
- The A is nutrients and algae, 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.
Are there campgrounds on Dam Lake?
- Dam Lake has 3 public campgrounds from USGS The National Map within 5 km, including 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 grade
Low nutrients, clear water. The letter is not a swimming clearance.
Virginia's cleanest and most-polluted lakes, ranked
More Virginia Lake Rankings
Other Grade A 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)
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
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles