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LakeQuality

Dodge Pond-Deep Spot

Grafton County, New Hampshire55 acresView mapDirections

NHDES publishes the water-quality measurements for Dodge Pond-Deep Spot. Here is what has been measured.

Phosphorus
14.1 µg/L
Typical for New Hampshire
Measured by NHDES
Chlorophyll-a
8.5 µg/L
More algae than most
Measured by NHDES
Area
55 acres
Surface area
Type
Mesotrophic
Trophic class
  • Mesotrophic
  • Impaired · Algal growth

Dodge Pond-Deep Spot in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 14.1 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Surface area: 55 acres.

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Dodge Pond-Deep Spot is a 55-acre mesotrophic lake in Grafton County, New Hampshire. Compared to the 26 other monitored lakes in Grafton County, Dodge Pond-Deep Spot ranks #16 for water quality.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-07-06. Methodology: how these readings are compared.

Swimming conditions

Readings only

Low 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. Dodge Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.

Whether Dodge Pond-Deep Spot 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 Dodge Pond-Deep Spot

These are the measurements NHDES publishes for Dodge Pond-Deep Spot, 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 14.1 µg/L. Chlorophyll-a 8.5 µg/L. TSI 47.

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 phosphorus14.1µg/LGood
GoodFairPoor
Chlorophyll-a (algae)8.5µg/LMeasured, not scored

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.47Mesotrophic
OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

Ask about Dodge Pond-Deep Spot

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

Lake Details

Surface area

55 acres

No bathymetric survey has been published for Dodge Pond-Deep Spot, so its depth is not documented here.

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Stays near Dodge Pond-Deep Spot

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Fishing Dodge Pond-Deep Spot

Reservoir Info (USACE NID)

Dodge Pond-Deep Spot is a man-made reservoir impounded by the Dodge Pond Dam (completed 1936), built primarily for recreation on the Tr Ogontz Lake; concrete-type dam, 13 ft tall and 75 ft long.

Surface area
55 ac
Normal storage
150 ac-ft
Max storage
190 ac-ft
Drainage area
4.27 sq mi
Hazard class
Low
Owner
TOWN OF LYMAN

Source: USACE National Inventory of Dams, NID ID NH00146 · Operator website · Matched by proximity (0.25 km)

EPA Impairment Status

Dodge Pond-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Algal growthMercuryNutrients (phosphorus, nitrogen)

Designated uses not supporting: Aquatic life, Fish consumption.

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

Source: EPA ATTAINS assessment unit NHLAK801030502-01 · Official waterbody report

Nearby Lakes in Grafton County

Frequently asked questions about Dodge Pond-Deep Spot

Where is Dodge Pond-Deep Spot?

Dodge Pond-Deep Spot is a lake in Grafton County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.

What is the water quality of Dodge Pond-Deep Spot?

Dodge Pond-Deep Spot in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 14.1 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Surface area: 55 acres.

Measurements on this page ↑

Is Dodge Pond-Deep Spot safe to swim in?

Nutrient and algae readings are not a swimming clearance. Dodge Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.

Swimming on this page ↑

Where this data comes from

12 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.

Collected and reported by

  • New Hampshire Department Of Environmental Services (BEACH)1111330012 samples · 2021–2025

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