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LakeQuality

Wicwas Lake-Marion Cove

Belknap County, New Hampshire330 acresView mapDirections

NHDES publishes the water-quality measurements for Wicwas Lake-Marion Cove. Here is what has been measured.

Phosphorus
6.9 µg/L
Less phosphorus than most
Measured by NHDES
Area
330 acres
Surface area
Type
Oligotrophic
Trophic class
  • Oligotrophic
  • Impaired · Mercury
  • Limited data

Wicwas Lake-Marion Cove in Belknap County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 6.9 µg/L. Surface area: 330 acres.

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Wicwas Lake-Marion Cove is a 330-acre cold, clear oligotrophic lake in Belknap County, New Hampshire. Compared to the 26 other monitored lakes in Belknap County, Wicwas Lake-Marion Cove ranks #19 for water quality.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-06-26. Methodology: how these readings are compared.

Swimming conditions

Readings only

Limited data

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. Wicwas Lake-Marion Cove is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.

Whether Wicwas Lake-Marion Cove is safe to swim in today is a call for the New Hampshire Department of Environmental Services and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Wicwas Lake-Marion Cove

These are the measurements NHDES publishes for Wicwas Lake-Marion Cove, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

No clarity data. Phosphorus 6.9 µg/L. TSI 32.

Water quality readings
MeasureReadingWhere it sits
Water clarity (Secchi depth)No reading

How deep a black-and-white disk stays visible from the surface. Higher is clearer.

Total phosphorus6.9µg/LGood
GoodFairPoor
Chlorophyll-a (algae)No reading

The green pigment in algae — a direct measure of how much algae is in the water.

Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a.32Oligotrophic
OligotrophicMesotrophicEutrophicHypereutrophic

Low nutrients, clear water. No reading is a swimming clearance.

Ask about Wicwas Lake-Marion Cove

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

Lake Details

Surface area

330 acres

No bathymetric survey has been published for Wicwas Lake-Marion Cove, so its depth is not documented here.

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Fishing Wicwas Lake-Marion Cove

Reservoir Info (USACE NID)

Wicwas Lake-Marion Cove is a man-made reservoir impounded by the Lake Wicwas Dam (completed 1937), built primarily for recreation on the Dolloff Brook; earth-type dam, 7 ft tall and 190 ft long.

Surface area
330 ac
Normal storage
457 ac-ft
Max storage
1,567 ac-ft
Drainage area
8.46 sq mi
Hazard class
Low
Owner
TOWN OF MEREDITH

Source: USACE National Inventory of Dams, NID ID NH00124 · Operator website · Matched by proximity (0.52 km)

EPA Impairment Status

Wicwas Lake-Marion Cove is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryOxygen depletion (low DO)pH / acidity

Designated uses not supporting: Aquatic life, Fish consumption.

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit NHLAK700020201-04 · Official waterbody report

Nearby Lakes in Belknap County

Frequently asked questions about Wicwas Lake-Marion Cove

Where is Wicwas Lake-Marion Cove?

Wicwas Lake-Marion Cove is a lake in Belknap County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.

What is the water quality of Wicwas Lake-Marion Cove?

Wicwas Lake-Marion Cove in Belknap County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 6.9 µg/L. Surface area: 330 acres.

Measurements on this page ↑

Is Wicwas Lake-Marion Cove safe to swim in?

Nutrient and algae readings are not a swimming clearance. Wicwas Lake-Marion Cove is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.

Swimming on this page ↑

Where this data comes from

3 measurements from 1 monitoring station, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.

Collected and reported by

  • New Hampshire Department Of Environmental Services (BEACH)111133003 samples · 2023–2025

Analytical methods

  • 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
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