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Lake Frederick-Right Arm

Frederick County, Virginia91 acresView mapDirections

Virginia DEQ publishes the water-quality measurements for Lake Frederick-Right Arm. Here is what has been measured.

Clarity
9.2 ft
Secchi · sampled 2026
Phosphorus
20 µg/L
Measured by Virginia DEQ
Chlorophyll-a
4.7 µg/L
Measured by Virginia DEQ
Area
91 acres
Surface area
Type
Mesotrophic
Trophic class
Trend
Declining
10 years of samples
  • Mesotrophic

Ask about Lake Frederick-Right Arm

Answers come straight from the public measurements and survey records on this page.

Lake Frederick-Right Arm in Frederick County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.7 µg/L. Surface area: 91 acres.

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Lake Frederick-Right Arm is a 91-acre mesotrophic lake in Frederick County, Virginia. Overall water quality is declining over recent sampling years. Compared to the 1 other monitored lakes in Frederick County, Lake Frederick-Right Arm ranks #2 for water quality.

Source: EPA Water Quality Portal sampling records, Virginia DEQ, last sampled 2026-07-07. Grade methodology: LakeQuality methodology.

Swimming conditions

Readings only

Moderate 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 Lake Frederick-Right Arm 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.

Get alerts for Lake Frederick-Right Arm

Water quality measurements for Lake Frederick-Right Arm

These are the measurements Virginia DEQ publishes for Lake Frederick-Right Arm, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

Moderate clarity, visible to about 9.2 ft. Phosphorus 20 µg/L. Chlorophyll-a 4.7 µg/L. TSI 46.

MetricValueEPA condition class
Water Clarity (Secchi Depth)9.2 ftMeasured, not scored
Phosphorus20 µg/LFair
Chlorophyll-a (Algae)4.7 µg/LGood
Trophic State Index (TSI)46Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Surface Area91 acres

No bathymetric survey has been published for Lake Frederick-Right Arm, so its depth is not documented here.

Fishing Lake Frederick-Right Arm

Based on 10 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.152 m/yr10
Phosphorus Declining+0.58 µg/L/yr10
Chlorophyll-a Declining+0.14 µg/L/yr10
See year-by-year chart →

Reservoir Info (USACE NID)

Lake Frederick-Right Arm is a man-made reservoir impounded by the Lake Frederick Dam, built primarily for recreation on the Crooked Run; earth-type dam, 74 ft tall and 680 ft long.

Surface area
91 ac
Normal storage
2,410 ac-ft
Max storage
4,300 ac-ft
Drainage area
3 sq mi
Hazard class
High
Owner
Virginia Department of Wildlife Resources

Source: USACE National Inventory of Dams, NID ID VA069013 · Operator website · Matched by proximity (0.99 km)

Nearby Lakes in Frederick County

Frequently asked questions about Lake Frederick-Right Arm

Where is Lake Frederick-Right Arm?

Lake Frederick-Right Arm is a lake in Frederick County, Virginia. Its water-quality measurements are published by Virginia DEQ and shown on this page as reported.

What is the water quality of Lake Frederick-Right Arm?

Lake Frederick-Right Arm in Frederick County, Virginia has water-quality measurements published by Virginia DEQ, shown here as reported. Water clarity: 9.2 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.7 µg/L. Surface area: 91 acres.

Is Lake Frederick-Right Arm safe to swim in?

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Where this data comes from

259 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 QUALITY21VASWCB259 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
  • 2130 B ~ Nephelometric Method
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.