Martinsville Reservoir
Henry County, Virginia206 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Mesotrophic
- Impaired · Pathogens (E. coli, fecal)
- #1 of 1 in the county
- 46 ft max depth
Martinsville Reservoir in Henry County, Virginia has a water quality grade of A (Excellent). Water clarity: 8.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Surface area: 206.4 acres.
- Clarity
- 8.5 ft
- Max depth
- ~46 ft est.
- Area
- 206 acres
- Type
- Mesotrophic
- Phosphorus
- 10 µg/L
- Chlorophyll-a
- 2.1 µg/L
- Trend
- ↑ Improving
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Watch Martinsville Reservoir’s letter
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Martinsville Reservoir is a 206-acre mesotrophic lake in Henry County, Virginia with an estimated average depth of about 46 feet. Water quality is graded A based on 2 sampling years through 2026. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Virginia DEQ, last sampled 2026-07-09. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyBacteria advisory
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. Martinsville Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for pathogens (E. coli, fecal). Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 8.5 ft. Phosphorus 10 µg/L. Chlorophyll-a 2.1 µg/L. TSI 41. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.5 ft | Not graded |
| Phosphorus | 10 µg/L | Good |
| Chlorophyll-a (Algae) | 2.1 µg/L | Good |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~46 ft est. |
| Average Depth | ~20 ft est. |
| Surface Area | 206 acres |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Virginia has not published bathymetry for Martinsville Reservoir.
Lake Size & Watershed
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.
Fishing Martinsville Reservoir
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.011 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.53 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.12 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Martinsville Reservoir is a man-made reservoir impounded by the Beaver Creek Dam, built primarily for water supply on the Beaver Creek - VAHU6 RD24 Smith River - Beaver Creek; earth-type dam, 71 ft tall and 1,500 ft long.
- Surface area
- 206.4 ac
- Normal storage
- 4,066 ac-ft
- Max storage
- 6,603 ac-ft
- Drainage area
- 9.68 sq mi
- Hazard class
- High
- Owner
- City of Martinsville
Source: USACE National Inventory of Dams, NID ID VA089003 · Operator website · Matched by proximity (0.13 km)
EPA Impairment Status
Martinsville Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit VAW-L53L_BAU01A02 · Official waterbody report · Matched by proximity (1.05 km)
County Ranking
Ranked #1 of 1 lakes in Henry County
Nearby Lakes in Henry County
Frequently asked questions about Martinsville Reservoir
Where is Martinsville Reservoir?
- Martinsville Reservoir is a lake in Henry County, Virginia. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Martinsville Reservoir?
- Martinsville Reservoir in Henry County, Virginia has a water quality grade of A (Excellent). Water clarity: 8.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.1 µg/L. Surface area: 206.4 acres.
Is Martinsville Reservoir safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Martinsville Reservoir is listed impaired under Clean Water Act §303(d) (IR 4A) for pathogens (E. coli, fecal). Check local advisories before you swim.
How deep is Martinsville Reservoir?
- No published bathymetric survey covers Martinsville Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 46 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 206.4 acres.
Explore Martinsville Reservoir across LakeQuality
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Where this data comes from
274 measurements from 1 monitoring station, 2014–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- VIRGINIA DEPARTMENT OF ENVIRONMENTAL QUALITY
21VASWCB274 samples · 2014–2026
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
- 2130 B ~ Nephelometric Method
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)