Powwow River Lake
Rockingham County, New Hampshire353 acresView mapDirections
NHDES publishes the water-quality measurements for Powwow River Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
Powwow River Lake in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 3.9 µg/L. Surface area: 353 acres.
Powwow River Lake is a 353-acre mesotrophic lake in Rockingham County, New Hampshire. Compared to the 50 other monitored lakes in Rockingham County, Powwow River Lake ranks #23 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-20. Methodology: how these readings are compared.
Swimming conditions
Readings onlyModerate 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. Powwow River Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nuisance exotic species, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
Whether Powwow River Lake 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.
Water quality measurements for Powwow River Lake
These are the measurements NHDES publishes for Powwow River Lake, 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 18 µg/L. Chlorophyll-a 3.9 µg/L. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 18µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 3.9µg/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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Lake Details
Surface area
353 acres
No bathymetric survey has been published for Powwow River Lake, so its depth is not documented here.
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Fishing Powwow River Lake
Reservoir Info (USACE NID)
Powwow River Lake is a man-made reservoir impounded by the Powwow Pond Dam (completed 1935), built primarily for recreation on the Powwow River; earth-type dam, 12 ft tall and 250 ft long.
- Surface area
- 353 ac
- Normal storage
- 1,472 ac-ft
- Max storage
- 3,761 ac-ft
- Drainage area
- 29.36 sq mi
- Hazard class
- Significant
- Owner
- NH DES WATER DIVISION
Source: USACE National Inventory of Dams, NID ID NH00440 · Operator website · Matched by proximity (0.28 km)
EPA Impairment Status
Powwow River Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHIMP700061403-04 · Official waterbody report
Nearby Lakes in Rockingham County
Frequently asked questions about Powwow River Lake
Where is Powwow River Lake?
- Powwow River Lake is a lake in Rockingham County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Powwow River Lake?
- Powwow River Lake in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 3.9 µg/L. Surface area: 353 acres.
Is Powwow River Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Powwow River Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nuisance exotic species, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
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Where this data comes from
27 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330027 samples · 2020–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
- CHLOROPHYLL A-B-C DETERMINATION (MODIFIED)
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